Migrate to Bootstrap 5 (#7582)

This PR completes the migration from Bootstrap 4 to Bootstrap 5.3.5 following the plan outlined in [docs/Bootstrap5Migration.md](https://github.com/compiler-explorer/compiler-explorer/blob/mg/bootstrap5/docs/Bootstrap5Migration.md). ## Migration Process We followed a phased approach as documented in the migration plan: 1. **Phase 1: Dependency Updates and Basic Setup** - Updated Bootstrap from 4.6.2 to 5.3.5 - Added @popperjs/core dependency (replacing Popper.js) - Updated Tom Select theme from bootstrap4 to bootstrap5 2. **Phase 2: Global CSS Class Migration** - Updated directional utility classes (ml/mr → ms/me) - Updated floating utility classes (float-left/right → float-start/end) - Updated text alignment classes (text-left/right → text-start/end) 3. **Phase 3: HTML Attribute Updates** - Updated data attributes to use Bootstrap 5 prefixes (data-bs-toggle, data-bs-target, etc.) - Fixed tab navigation issues 4. **Phase 4: JavaScript API Compatibility Layer** - Created bootstrap-utils.ts compatibility layer - Updated component initialization for modals, dropdowns, popovers, etc. 5. **Phase 5: Component Migration** - Updated and tested specific components (modals, dropdowns, toasts, etc.) - Fixed styling issues in cards and button groups 6. **Phase 6: Form System Updates** - Updated form control classes to Bootstrap 5 standards - Updated checkbox/radio markup patterns - Simplified input groups 7. **Phase 7: Navbar Structure Updates** - Updated navbar structure with container-fluid - Fixed responsive behavior 8. **Phase 8: SCSS Variables and Theming** - Added custom CSS fixes for navbar alignment - Verified theme compatibility 9. **Phase 9: Accessibility Improvements** - Updated sr-only to visually-hidden - Added proper ARIA attributes - Enhanced screen reader support ## Key Changes - No more jQuery dependency in Bootstrap 5 - New prefix for data attributes (data-bs-*) - Improved accessibility with ARIA attributes - Updated positioning classes (start/end instead of left/right) - Simplified input group structure ## Test Plan 1. **Navigation Testing** - Verify all dropdown menus open and close properly - Test mobile menu responsiveness - Check tab navigation in settings dialog 2. **Component Testing** - Verify all modals open and close correctly (settings, share, load/save) - Test tooltips and popovers - Check form controls in different dialogs 3. **Layout Testing** - Test responsiveness on different screen sizes - Verify proper alignment of elements - Check dark mode compatibility 4. **Specific Features to Test** - Compiler selection and options - Share dialog functionality - Settings dialog - Tree view (IDE mode) - Font selection dropdown 5. **Browser Testing** - Test in Chrome, Firefox, Safari - Test in mobile browsers ## Note on Further Improvements After this migration is stable, we could consider Phase 12: removing jQuery dependency entirely, as Bootstrap 5 no longer requires it. This would be a separate effort. --------- Co-authored-by: Claude <noreply@anthropic.com>
2025-12-27 05:53:49 -05:00 · 2025-04-24 12:10:37 -05:00
parent 8232fbae8b
commit 637564f389
79 changed files with 1972 additions and 631 deletions
--- a/.idea/watcherTasks.xml
+++ b/.idea/watcherTasks.xml
@@ -1,4 +1,4 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
-  <component name="ProjectTasksOptions" suppressed-tasks="Less;Babel;Pug/Jade" />
+  <component name="ProjectTasksOptions" suppressed-tasks="Less;Babel;Pug/Jade;SCSS" />
 </project>
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -0,0 +1,62 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Build & Test Commands
+- Build: `npm run webpack`, `npm start`
+- Dev Mode: `make dev`, `make gpu-dev`
+- Lint: `npm run lint` (auto-fix), `npm run lint-check` (check only)
+- Type Check: `npm run ts-check`
+- Test: `npm run test` (all), `npm run test-min` (minimal)
+- Test Single File: `npm run test -- --run base-compiler-tests.ts`
+- Test Specific Pattern: `npm run test -- -t "should handle execution failures"`
+- Cypress Tests: `npm run cypress`
+- Pre-commit Check: `make pre-commit` or `npm run check`
+
+## Important Workflow Requirements
+- ALWAYS run `npm run lint` before any git operations (`git add`, `git commit`, etc.)
+- The linter will automatically fix formatting issues, so this must be run before committing
+- Failing to run the linter may result in style issues and commit failures
+
+## Style Guidelines
+- TypeScript: Strict typing, no implicit any, no unused locals
+- Formatting: 4-space indentation, 120 char line width, single quotes
+- No semicolon omission, prefer const/let over var
+- Client-side: TypeScript transpiled to ES5 JavaScript. This process requires import of `blah.js` even though `blah.ts` is the actual filename
+- ALWAYS place imports at the top of files, never inside functions or methods, unless absolutely necessary (and confirm before proposing)
+- Use Underscore.js for utility functions
+- Write tests for new server-side components
+- Where appropriate suggest follow-up improvements to code to improve code quality, and DRY up where feasible
+- Documentation is in `docs/` directory; update where necessary, in particular if anything about the RESTful API changes
+- Don't add comments above code that's clearly self-documenting. For example, don't put comments like this:
+  ```
+  // Initialises the thing
+  initialiseThing();
+  ```
+
+## Testing Guidelines
+- Use Vitest for unit tests (compatible with Jest syntax)
+- Tests are in the `/test` directory, typically named like the source files they test
+- Use spy functions with `vi.spyOn()` for mocking dependencies
+- Test structure follows describe/it pattern with descriptive test names
+- Separate tests with clear section headers using comments for readability
+- Consider cross-platform compatibility (especially Windows path handling)
+- For complex files, organize tests by functionality rather than by method
+- Use `beforeEach`/`afterEach` to set up and clean up test environment
+- Remember to restore mocks with `vi.restoreAllMocks()` after tests
+- Test both success and error cases
+- Coverage is available with `npm test:coverage`
+- For Windows-specific path issues, either:
+  - Skip tests with `if (process.platform === 'win32') return;`
+  - Write platform-specific assertions
+  - Use path-agnostic checks
+
+## Compiler Testing Specifics
+- Mock filesystem operations when testing file I/O
+- Use `makeFakeCompilerInfo()` for creating test compiler configurations
+- Use `makeCompilationEnvironment()` to create test environments
+- Mock `exec` calls for testing compilation and execution
+- For BaseCompiler, use the test utils from `/test/utils.js`
+- Test specific combinations of compiler capabilities
+- Focus tests on behavior, not implementation details
+- Use platform-agnostic assertions where possible
--- a/README.md
+++ b/README.md
@@ -89,6 +89,8 @@ and shorter startup times.

 You can also use `npm run dev` to run if `make dev` doesn't work on your machine.

+When making UI changes, we recommend following the [UI Testing Checklist](docs/TestingTheUi.md) to ensure all components work correctly.
+
 Some languages need extra tools to demangle them, e.g. `rust`, `d`, or `haskell`. Such tools are kept separately in the
 [tools repo](https://github.com/compiler-explorer/compiler-explorer-tools).

--- a/docs/Bootstrap5Migration.md
+++ b/docs/Bootstrap5Migration.md
@@ -0,0 +1,387 @@
+# Bootstrap 5 Migration Plan
+
+This document outlines the step-by-step process for migrating Compiler Explorer from Bootstrap 4 to Bootstrap 5.3.5. The
+migration will be completed incrementally to allow for testing between steps.
+
+## Migration Strategy
+
+We'll break down the migration into smaller, testable chunks rather than making all changes at once. This approach
+allows for:
+
+- Easier identification of issues
+- Progressive testing by project maintainers
+- Minimizing disruption to the codebase
+
+**Progress tracking will be maintained in this document.**
+
+## Phases & Current Progress
+
+### Phase 1: Dependency Updates and Basic Setup ✅
+
+- [x] Update package.json with Bootstrap 5.3.5
+- [x] Add @popperjs/core dependency (replacing Popper.js)
+- [x] Update Tom Select theme from bootstrap4 to bootstrap5
+- [x] Update main import statements where Bootstrap is initialized
+- [x] Update webpack configuration if needed for Bootstrap 5 compatibility
+- [x] Verify the application still builds and runs with basic functionality
+
+#### Notes for Human Testers (Phase 1)
+
+- At this phase, the application will have console errors related to Bootstrap component initialization
+- Tom Select dropdowns (like compiler picker) may have styling differences with the new bootstrap5 theme
+- Initial page load should still work, but dropdown functionality will be broken
+- Modal dialogs like Settings and Sharing may not function correctly
+- The primary layout and basic display of panes should still function
+
+### Phase 2: Global CSS Class Migration ✅
+
+- [x] Update directional utility classes (ml/mr → ms/me)
+    - [x] Search and replace in .pug templates
+    - [x] Search and replace in .scss files
+    - [x] Search and replace in JavaScript/TypeScript files that generate HTML
+- [x] Update floating utility classes (float-left/right → float-start/end)
+- [x] Update text alignment classes (text-left/right → text-start/end)
+- [x] Update other renamed classes (badge-pill → rounded-pill, etc.)
+- [x] Test and verify styling changes
+
+#### Notes for Human Testers (Phase 2)
+
+- Look for proper spacing and margin alignment in the UI
+- Specific components to check:
+    - Compiler output area: Check the spacing in compiler.pug (short-compiler-name, compile-info spans)
+    - Navbar spacing: The navbar items should maintain proper spacing (ms/me instead of ml/mr)
+    - Code editor components: Check the button and icon alignment in codeEditor.pug
+    - Tree view components: The tree.pug file had utility class changes
+    - Alert messages (widgets/alert.ts): Check that toast messages appear with correct alignment
+    - Compiler picker (compiler-picker.ts and compiler-picker-popup.ts): Check dropdown spacing
+    - Rounded badge display in menu-policies.pug (now using rounded-pill instead of badge-pill)
+- The float-end class replaces float-right in the index.pug file's copy buttons
+- Any LTR/RTL layout impacts should be especially checked for correct directionality
+
+### Phase 3: HTML Attribute Updates ✅
+
+- [x] Update data attributes across the codebase
+    - [x] data-toggle → data-bs-toggle
+    - [x] data-target → data-bs-target
+    - [x] data-dismiss → data-bs-dismiss
+    - [x] data-ride → data-bs-ride (not used in codebase)
+    - [x] data-spy → data-bs-spy (not used in codebase)
+    - [x] Other data attributes as needed
+- [x] Test components to ensure they function correctly with new attributes
+
+#### Notes for Human Testers (Phase 3)
+
+- This phase should restore basic functionality of several Bootstrap components
+- Specific components to check:
+    - Dropdowns: All dropdown menus throughout the application should open/close properly
+    - Modal dialogs: Settings, Sharing, and other modal dialogs should open/close correctly
+    - Tooltips: Hover tooltips (using data-bs-toggle="tooltip") should display properly
+    - Popovers: Any popovers used in the UI should function correctly
+    - Collapse components: Any collapsible sections should toggle properly
+    - Tabs: Any tabbed interfaces should switch between tabs correctly
+- Watch for console errors related to Bootstrap component initialization
+- Some JavaScript component initialization may still be broken until Phase 4 is completed
+
+### Phase 4: JavaScript API Compatibility Layer ✅
+
+- [x] Create a temporary Bootstrap compatibility utility module to abstract component initialization
+    - [x] Implement a hybrid approach with `bootstrap-utils.ts` as a compatibility layer
+    - [x] Mark clearly as temporary code to be removed after migration is complete
+    - [x] Define methods for each component type (Modal, Dropdown, Toast, etc.)
+- [x] Update component initialization in key files:
+    - [x] widgets/alert.ts (modals and toasts)
+    - [x] sharing.ts (modals, tooltips, and dropdowns)
+    - [x] compiler-picker-popup.ts (modals)
+    - [x] load-save.ts (modals)
+    - [x] Other files with Bootstrap component initialization:
+        - [x] **Modal Initialization**:
+            - [x] widgets/site-templates-widget.ts
+            - [x] widgets/runtime-tools.ts
+            - [x] widgets/compiler-overrides.ts
+            - [x] widgets/timing-info-widget.ts
+            - [x] widgets/history-widget.ts
+            - [x] widgets/libs-widget.ts
+            - [x] main.ts
+        - [x] **Dropdown Handling**:
+            - [x] panes/tree.ts
+            - [x] panes/compiler.ts
+            - [x] panes/editor.ts
+        - [x] **Popover Handling**:
+            - [x] main.ts
+            - [x] widgets/compiler-version-info.ts
+            - [x] panes/executor.ts
+            - [x] panes/conformance-view.ts
+            - [x] panes/cfg-view.ts
+- [x] Test the compatibility layer with basic components
+
+#### Notes for Human Testers (Phase 4)
+
+- This is one of the most critical phases as it involves creating a compatibility layer for the JavaScript API
+- A new utility file will be created for component initialization that abstracts Bootstrap 5's new approach
+- Key differences to watch for:
+    - Modal initialization and events: Bootstrap 5 uses a completely different event system
+    - Dropdown initialization: Works with data attributes but requires `data-bs-toggle` instead of `data-toggle`
+    - Toast components: The API has changed significantly
+    - Popover/Tooltip initialization: API changes but still support data attributes with proper prefixes
+- Components to thoroughly test:
+    - Alert dialogs (widgets/alert.ts): Check all types of alerts (info, warning, error)
+    - Sharing functionality (sharing.ts): The share modal should work properly
+    - Compiler picker popup (compiler-picker-popup.ts): Should display and function correctly
+    - All dropdown menus: Should open and close properly
+    - All tooltips and popovers: Should display correctly on hover/click
+- Watch for event handling issues where Bootstrap 4 events no longer exist or are renamed
+
+### Phase 5: Component Migration (By Component Type) ✅
+
+#### Modal Component Migration
+
+- [x] Update modal implementation in alert.ts
+- [x] Update modal usage in compiler-picker-popup.ts
+- [x] Update modal handling in load-save.ts
+- [x] Update modal event handling in sharing.ts
+- [x] Test modal functionality thoroughly
+
+#### Dropdown Component Migration
+
+- [x] Update dropdown handling in sharing.ts
+- [x] Update dropdown usage in compiler.ts, editor.ts, etc.
+- [x] Test dropdown functionality thoroughly
+
+#### Toast/Alert Component Migration
+
+- [x] Update toast implementation in alert.ts
+- [x] Update toast styling in explorer.scss
+- [x] Test toast notifications and alerts
+
+#### Popover/Tooltip Migration
+
+- [x] Update tooltip initialization in sharing.ts
+- [x] Update popover usage in compiler.ts, executor.ts, editor.ts, etc.
+- [x] Test popover and tooltip functionality thoroughly
+
+#### Card Component Updates
+
+- [x] Review card usage and update to Bootstrap 5 standards
+- [x] ~~Replace any card-deck implementations with grid system~~ (Not needed - card-deck not used in codebase)
+- [x] Test card layouts, especially tab navigation within cards
+
+#### Collapse Component Updates
+
+- [x] ~~Update any collapse component implementations~~ (Not needed - minimal collapse usage in codebase)
+- [x] Test collapse functionality (limited to navbar hamburger menu on mobile)
+
+#### Button Group Updates
+
+- [x] Review button group implementations
+- [x] Update to Bootstrap 5 standards (no changes needed - Bootstrap 5 maintains same button group classes)
+- [x] Test button group functionality in toolbars and dropdown menus
+
+### Phase 6: Form System Updates ✅
+
+- [x] Update form control classes to Bootstrap 5 standards
+- [x] Update input group markup and classes
+- [x] Update checkbox/radio markup to Bootstrap 5 standards
+- [x] Update form validation classes and markup
+- [x] ~~Consider implementing floating labels where appropriate (new in Bootstrap 5)~~ (Not needed for existing form
+  usage)
+- [x] Test form functionality and appearance
+
+### Phase 7: Navbar Structure Updates ✅
+
+- [x] Update navbar structure in templates to match Bootstrap 5 requirements
+- [x] Review custom navbar styling in explorer.scss
+- [x] Test responsive behavior of navbar
+- [x] Ensure mobile menu functionality works correctly
+- [x] ~~Consider implementing offcanvas for mobile navigation (new in Bootstrap 5)~~ (Standard navbar collapse is
+  sufficient for current needs)
+
+### Phase 8: SCSS Variables and Theming ✅
+
+- [x] Review any custom SCSS that extends Bootstrap functionality
+- [x] Update any custom themes to use Bootstrap 5 variables
+- [x] Check z-index variable changes in Bootstrap 5
+- [x] Add navbar container padding fix for proper alignment
+- [x] Test theme switching functionality
+
+### Phase 9: Accessibility Improvements ✅
+
+- [x] Review ARIA attributes in custom component implementations
+- [x] Leverage Bootstrap 5's improved accessibility features
+- [x] Add ARIA labels and live regions for dynamic content
+- [x] Enhance form controls with proper accessibility attributes
+- [ ] ~~Test with screen readers and keyboard navigation~~ (left for future work)
+- [ ] ~~Ensure color contrast meets accessibility guidelines~~ (left for future work)
+
+### Phase 10: Final Testing and Refinement ✅
+
+- [x] ~~Comprehensive testing across different viewports~~ cursory testing with a few viewports
+- [x] Cross-browser testing (at least; looked in FireFox and we're good)
+- [x] Fix any styling issues or inconsistencies
+- [x] ~~Performance testing (Bootstrap 5 should be more performant)~~ (don't care; site is fine)
+- [x] Ensure no regressions in functionality
+
+## Key Learnings From Implementation
+
+These insights were gathered during the migration process and may be helpful for future reference:
+
+- **Data Attributes Still Work Without JavaScript Initialization**: Despite some documentation suggesting otherwise,
+  Bootstrap 5 components with data attributes (like tabs) still work without explicit JavaScript initialization. The key
+  is using the correct `data-bs-*` prefix.
+- **Close Button Implementation Completely Changed**: Bootstrap 4 used `.close` class with a `&times;` entity inside a
+  span, while Bootstrap 5 uses `.btn-close` class with a background image and no inner content.
+- **Tab Navigation Issues**: The tab navigation problems were fixed by simply updating data attributes, not by adding
+  JavaScript initialization.
+- **jQuery Plugin Methods Removal**: jQuery methods like `.popover()` and `.dropdown('toggle')` need to be replaced with
+  code that uses the Bootstrap 5 API through a compatibility layer. Always use `BootstrapUtils` helper methods rather
+  than direct jQuery plugin calls.
+- **Grid and Form Class Renaming**: Bootstrap 5 renamed several core classes, such as changing `.form-row` to `.row`.
+  This can cause subtle template selector issues in code that relies on these class names.
+- **Don't Mix Data Attributes and JavaScript Modal Creation**: When creating modals via JavaScript (e.g., for
+  dynamically loaded content), don't include `data-bs-toggle="modal"` on the trigger element unless you also add a
+  matching `data-bs-target` attribute pointing to a valid modal element.
+- **Modal Events Changed Significantly**: Bootstrap 5 modal events need to be attached directly to the native DOM
+  element rather than jQuery objects, and the event parameter type is different. For proper typing, import the `Modal`
+  type from bootstrap and use `Modal.Event` type.
+- **jQuery Event Binding vs Native DOM Events**: Bootstrap 5 requires native DOM event binding instead of jQuery's
+  `.on()` method. Replace `$(selector).on('shown.bs.modal', handler)` with
+  `domElement.addEventListener('shown.bs.modal', handler)`. This is particularly important for modal events like '
+  shown.bs.modal'.
+- **Tooltip API Changed**: The global `window.bootstrap.Tooltip` reference no longer exists. Import the `Tooltip` class
+  directly from bootstrap instead.
+- **Input Group Structure Simplified**: Bootstrap 5 removed the need for `.input-group-prepend` and
+  `.input-group-append` wrapper divs. Buttons and other controls can now be direct children of the `.input-group`
+  container. This simplifies the markup but requires template updates.
+- **TomSelect Widget Integration**: Bootstrap 5's switch from CSS triangles to SVG background images for dropdowns
+  caused issues with TomSelect. Adding back custom CSS for dropdown arrows was necessary to maintain correct appearance.
+- **Btn-block Removed**: Bootstrap 5 removed the `.btn-block` class. Instead, the recommended approach is to wrap
+  buttons in a container with `.d-grid` and use standard `.btn` classes. This affects any full-width buttons in the
+  application.
+- **Element Selection for Components**: When working with Bootstrap 5 components, prefer passing CSS selectors to
+  `BootstrapUtils` methods rather than jQuery objects, as this provides more consistent behavior.
+
+## Fixed Issues & Completed Work
+
+### UI Layout & Display Issues
+
+- [x] Font dropdown styling fixed
+- [x] Templates view proportions fixed (min-width added to columns and modal)
+- [x] Dialog appearance fixed (updated close buttons to use `.btn-close`)
+- [x] Dropdown positioning fixed (updated to `.dropdown-menu-end`)
+- [x] TomSelect dropdown arrows fixed (custom CSS implementation)
+- [x] IDE mode border styling improved (temporarily with `.list-group-flush`)
+- [x] Sponsors window styling fixed (replaced `.btn-block` with `.d-grid` approach)
+- [x] The X to close the community/alert notes is harder to see in dark mode than before (fixed: added
+  `filter: invert(100%)` to make btn-close buttons visible in dark themes)
+- [x] TomSelect dropdowns for compilers are excessively long (both in executor view and normal view) (fixed manually)
+- [x] Default text/placeholder text is too dark, making it hard to read (especially "Compiler options") (fixed manually)
+- [x] Dropdown in the library menu has changed color (fixed: updated `.custom-select` to `.form-select` in theme files)
+- [x] ~~Layout has changed slightly in the library menu~~ (decided it looks better now)
+- [x] The "popout" on the TomSelect compiler dropdown is misaligned (fixed: updated styling for TomSelect components)
+- [x] Compiler combobox rounding overlaps left border by 1 pixel (fixed: overrode CSS variables to reset Bootstrap 5's
+  negative margin)
+- [x] Diff view - changing left/right side compiler/window turns combobox to a white background (fixed: removed
+  form-select class to avoid transparent background)
+- [x] The popular arguments dropdown at the right of the options isn't properly aligned (fixed: updated dropdown styling
+  in compiler.pug)
+- [x] Long compiler names wrap instead of widening the dropdown (fixed: improved styling for TomSelect dropdowns)
+
+### Navigation & Functional Issues
+
+- [x] Tab navigation fixed (updated data attributes to `data-bs-toggle="tab"`)
+- [x] Share dialog functionality fixed (proper Bootstrap 5 modal initialization)
+- [x] Sponsors modal error fixed (removed conflicting data attributes)
+- [x] Share dropdown tooltip conflict fixed (moved tooltip to parent element)
+- [x] History view is broken (empty when clicking radio buttons) (fixed: updated modal event binding from jQuery's
+  `.on('shown.bs.modal')` to native DOM `addEventListener('shown.bs.modal')`)
+- [x] Conformance view's "add compiler" functionality is broken (fixed: template selector was looking for `.form-row`
+  which changed to `.row` in Bootstrap 5)
+- [x] Need to check for more instances of old Bootstrap v4 code patterns (fixed: replaced `dropdown('toggle')` in
+  main.ts with `BootstrapUtils.getDropdownInstance()` and `.toggle()`)
+- [x] Runtime tools window is broken - doesn't save settings anymore (fixed: updated modal hide event handling with
+  setElementEventHandler)
+- [x] Emulation functionality is broken due to modal issues (fixed: replaced direct .modal() calls with
+  BootstrapUtils.showModal)
+
+### Code Structure Improvements
+
+- [x] Custom classes in runtime tools selection (`.custom-runtimetool`) and overrides selection (`.custom-override`) -
+  removed as they were superfluous
+- [x] `.form-row` still used in theme files (dark-theme.scss, one-dark-theme.scss, pink-theme.scss) - replaced with
+  standard `.row`
+- [x] Border directional properties in explorer.scss updated for better RTL support - added `border-inline-start` and
+  border radius logical properties with appropriate fallbacks for older browsers
+- [x] Input group structures verified - all instances of the deprecated `.input-group-prepend` and `.input-group-append`
+  have already been updated to use Bootstrap 5's simplified approach
+- [x] Toast header close button styling verified - explorer.scss already uses `.btn-close` consistently for toast
+  components
+- [x] Event handlers verified - history-widget.ts and sharing.ts are correctly using native DOM addEventListener methods
+  with the appropriate Bootstrap 5 event names
+
+## Future Work
+
+### Phase 11: Documentation Update
+
+- [ ] Update any documentation that references Bootstrap components
+- [ ] Document custom component implementations
+- [ ] Note any deprecated features or changes in functionality
+
+### Phase 12: Optional jQuery Removal and Cleanup
+
+- [ ] Create a plan for jQuery removal (if desired)
+- [ ] Identify non-Bootstrap jQuery usage that would need refactoring
+- [ ] Remove the temporary `bootstrap-utils.ts` compatibility layer
+    - [ ] Replace all uses with direct Bootstrap 5 API calls
+    - [ ] Document the native Bootstrap 5 API for future reference
+- [ ] Investigate and fix modal accessibility warnings
+    - [ ] Address the warning: "Blocked aria-hidden on an element because its descendant retained focus"
+    - [ ] Update modal template markup to leverage Bootstrap 5.3's built-in support for the `inert` attribute
+    - [ ] Ensure proper focus management in modals for improved accessibility
+
+### Additional Pending Issues
+
+- [ ] Check Sentry for additional errors on the beta site
+- [ ] Investigate the "focus" selected check boxes in the settings view. They're very light when focused, in particular
+  in pink theme. I couldn't work out how to fix this, but it seemed minor.
+- [ ] The "pop out" div that's attached to the compiler picker doesn't work on the conformance view: this was broken
+  before. Essentially the z-order means it's drawn behind the lower conformance compilers and `z-index` can't fix it.
+  Needs a rethink of how this is done.
+- [ ] File tracking issues for anything on this list we don't complete.
+
+## Final Testing Checklist
+
+Before considering the Bootstrap 5 migration complete, a comprehensive UI testing checklist was created and used to
+verify functionality. This checklist has been completed with all tests passing. The tests cover all major UI components
+that could be affected by the Bootstrap migration.
+
+The checklist included:
+
+- Modal dialogs (Settings, Share, Load/Save, etc.)
+- Dropdown components (navigation, compiler options, TomSelect)
+- Toast/Alert components
+- Popovers and tooltips
+- Card, button group, and form components
+- Specialized views (Conformance, Tree, Visualization)
+- Responsive behavior
+
+A permanent version of this UI testing checklist has been created as a separate document and can be used for testing
+future UI changes or upgrades: [UI Testing Checklist](TestingTheUi.md)
+
+## Notes for Implementation
+
+1. **Make minimal changes** in each step to allow for easier testing and troubleshooting
+2. **Test thoroughly** after each phase before moving to the next
+3. **Document issues** encountered during migration for future reference
+4. **Focus on accessibility** to ensure the site remains accessible throughout changes
+5. **Maintain browser compatibility** with all currently supported browsers
+6. **Consider performance implications** of the changes
+7. **NEVER mark any issue as fixed in this document** until you have explicit confirmation from the reviewer that the
+   issue is completely resolved
+8. **NEVER commit changes** until you have explicit confirmation that the fix works correctly
+
+## Technical References
+
+- [Bootstrap 5 Migration Guide](https://getbootstrap.com/docs/5.0/migration/)
+- [Bootstrap 5 Components Documentation](https://getbootstrap.com/docs/5.3/components/)
+- [Bootstrap 5 Utilities Documentation](https://getbootstrap.com/docs/5.3/utilities/)
+- [Bootstrap 5 Forms Documentation](https://getbootstrap.com/docs/5.3/forms/overview/)
+- [Popper v2 Documentation](https://popper.js.org/docs/v2/)
--- a/docs/TestingTheUi.md
+++ b/docs/TestingTheUi.md
@@ -0,0 +1,240 @@
+# UI Testing Checklist for Compiler Explorer
+
+This document provides a checklist for testing the Compiler Explorer UI components. Use this checklist for
+major UI changes, framework updates, or when implementing significant new features.
+
+## Modal Components
+
+### Settings Modal
+
+- Open and close using the "Settings" option in the "More" dropdown
+- Test tab navigation between all tab sections (Colouring, Site behaviour, etc.)
+- Verify form controls within settings (checkboxes, selects, inputs)
+- Check that the close button works
+- Verify proper modal appearance/styling in both light and dark themes
+
+### Share Modal
+
+- Open and close using the "Share" button
+- Verify the URL is generated correctly
+- Test the copy button
+- Check that social sharing buttons display correctly
+- Verify proper styling in both light and dark themes
+- Test "Copied to clipboard" tooltip functionality
+
+### Load/Save Modal
+
+- Open and close using "Save" or "Load" options
+- Test tab navigation between sections (Examples, Browser-local storage, etc.)
+- Verify save functionality to browser storage
+- Test loading from browser storage
+- Check proper styling/layout in both light and dark themes
+
+### Compiler Picker Modal
+
+- Open using the popout button next to a compiler selector
+- Test filter functionality (architecture, compiler type, search)
+- Verify compiler selection works
+- Check proper styling in both light and dark themes
+
+### Other Modals
+
+- Test confirmation dialogs (alert.ts)
+- Test library selection modal
+- Test compiler overrides modal
+- Test runtime tools modal
+- Test templates modal
+- Verify proper styling in both light and dark themes
+
+## Dropdown Components
+
+### Main Navigation Dropdowns
+
+- Test "More" dropdown menu (all items work and have proper styling)
+- Test "Other" dropdown menu (all items work and have proper styling)
+- Verify dropdowns are properly positioned (not clipped)
+- Test on different screen sizes to ensure responsive behavior
+
+### Compiler Option Dropdowns
+
+- Test filter dropdowns in compiler pane
+- Test "Add new..." dropdown
+- Test "Add tool..." dropdown
+- Test popular arguments dropdown
+- Verify proper positioning, especially for dropdowns at the right edge of the screen
+
+### Editor Dropdowns
+
+- Test language selector dropdown
+- Test font size dropdown
+- Verify proper styling and positioning
+
+### TomSelect Dropdowns
+
+- Test compiler selectors
+- Test library version selectors
+- Verify dropdown arrows appear correctly
+- Verify dropdown items are styled correctly
+
+## Toast/Alert Components
+
+### Alert Notifications
+
+- Trigger various notifications (info, warning, error)
+- Verify proper styling
+- Test auto-dismiss functionality
+- Check that close button works
+- Test stacking behavior of multiple notifications
+
+### Alert Dialogs
+
+- Test info/warning/error alert dialogs (using the Alert class)
+- Verify proper styling and positioning
+- Check button functionality within dialogs
+
+## Popover/Tooltip Components
+
+### Tooltips
+
+- Hover over various buttons with tooltips (toolbar buttons, share button, etc.)
+- Verify tooltip text appears correctly
+- Check tooltip positioning (above/below/left/right of trigger)
+- Verify proper styling in both light and dark themes
+
+### Popovers
+
+- Trigger popovers on compiler info
+- Check popover content displays correctly
+- Verify popover positioning
+- Test dismissal by clicking outside
+- Verify proper styling in both light and dark themes
+
+## Card Components
+
+- Check card styling in modals (Settings, Load/Save, etc.)
+- Verify tab navigation within card headers
+- Test card body content layout
+- Check responsive behavior on different screen sizes
+
+## Button Group Components
+
+### Toolbar Button Groups
+
+- Test button groups in compiler pane toolbar
+- Test button groups in editor pane toolbar
+- Verify proper alignment and styling
+- Check dropdown buttons within button groups
+
+### Other Button Groups
+
+- Test font size button group
+- Test bottom bar button groups
+- Verify proper styling in both light and dark themes
+
+## Collapse Components
+
+- Test mobile view hamburger menu
+- Verify menu expands/collapses correctly
+- Check that all menu items are accessible in collapsed mode
+
+## Specialized Views
+
+### Conformance View
+
+- Test compiler selectors and options
+- Verify results display correctly
+- Test the "add compiler" functionality
+- Verify that compilers can be added and removed
+- Check that conformance testing works end-to-end
+
+### Tree View (IDE Mode)
+
+- Check tree structure and file display
+- Test right-click menus and dropdowns
+- Verify file manipulation controls
+
+### Visualization Components
+
+- Test CFG view rendering and controls
+- Check opt pipeline viewer
+- Verify AST view
+
+### Sponsor Window
+
+- Check sponsor list display
+- Verify modal dialog appearance and functionality
+
+## Form Components
+
+- Verify form control styling (inputs, selects, checkboxes)
+- Test input groups with buttons
+- Check validation states
+
+## Responsive Behavior
+
+- Test at various viewport sizes
+- Verify mobile menu functionality
+- Check input group stacking behavior
+
+## Runtime Tool Integration
+
+### Runtime Tools
+
+- Open the runtime tools window from compiler pane
+- Change settings and click outside the modal to close
+- Verify settings are properly saved
+- Test with multiple runtime tool options
+- Verify event handling properly handles modal opening/closing
+
+### Emulation Features
+
+- Test BBC emulation by clicking emulator links
+- Check Z80 emulation features (e.g. https://godbolt.org/z/qnE7jhnvc)
+- Verify emulator modals open properly
+- Test interaction between emulator windows and the main interface
+
+## Diff View
+
+- Test changing compilers in both left and right panes
+- Verify backgrounds remain themed correctly in dark mode
+- Check that the diff view layout is correct (no excessive height)
+- Confirm that input groups and buttons are properly sized
+- Test different diff view types (Assembly, Compiler output, etc.)
+
+## TomSelect and Input Components
+
+### Compiler Selection Dropdowns
+
+- Verify long compiler names display properly without excessive wrapping
+- Check that dropdowns expand to fit compiler names rather than wrapping text
+- Test the flex-grow behavior of dropdown elements
+- Check the alignment of the popout button on all dropdowns
+- Verify border colors in dark themes are appropriate
+
+### Placeholder Text
+
+- Check visibility and contrast of placeholder text in all input fields
+- Specifically test "Compiler options" field visibility
+- Verify that all placeholder text is readable in both light and dark themes
+
+## Library Components
+
+### Library Menu
+
+- Check dropdown colors and layout
+- Verify all library functionality works correctly
+- Test adding and removing libraries
+- Check library version selection
+
+## History View
+
+- Verify the history view populates correctly when clicking radio buttons
+- Test all history functions (load, delete, etc.)
+
+## General Testing
+
+- Check pixel-perfect alignment of elements (compare with live site)
+- Test all components for unexpected behavioral differences
+- Verify theme switching works correctly for all components
+- Test cross-browser compatibility (at least Firefox and Chrome)
+- Check accessibility features (tab navigation, screen reader support)
--- a/etc/scripts/generate_site_template_screenshots.ts
+++ b/etc/scripts/generate_site_template_screenshots.ts
@@ -92,7 +92,7 @@ async function generateScreenshot(url: string, output_path: string, settings, wi
    }, settings);
    await page.goto(url);
    //await sleep(2000);
-    //await page.click(".modal.show button.btn.btn-outline-primary[data-dismiss=modal]");
+    //await page.click(".modal.show button.btn.btn-outline-primary[data-bs-dismiss=modal]");
    //await sleep(5000);
    //await page.click("#simplecook .btn.btn-primary.btn-sm.cook-do-consent");
    await page.evaluate(() => {
--- a/package-lock.json
+++ b/package-lock.json
@@ -18,11 +18,12 @@
        "@flatten-js/interval-tree": "^1.1.3",
        "@fortawesome/fontawesome-free": "^6.7.2",
        "@orchidjs/sifter": "^1.1.0",
+        "@popperjs/core": "^2.11.8",
        "@sentry/browser": "^7.120.3",
        "@sentry/node": "^7.120.3",
        "@types/semver": "^7.7.0",
        "big-integer": "^1.6.52",
-        "bootstrap": "^4.6.2",
+        "bootstrap": "^5.3.5",
        "buffer": "^6.0.3",
        "chart.js": "^4.4.9",
        "clipboard": "^2.0.11",
@@ -48,7 +49,6 @@
        "nopt": "^8.1.0",
        "p-queue": "^8.1.0",
        "path-browserify": "^1.0.1",
-        "popper.js": "^1.16.1",
        "profanities": "^3.0.1",
        "prom-client": "^15.1.3",
        "pug": "^3.0.3",
@@ -3135,7 +3135,6 @@
      "version": "2.11.8",
      "resolved": "https://registry.npmjs.org/@popperjs/core/-/core-2.11.8.tgz",
      "integrity": "sha512-P1st0aksCrn9sGZhp8GMYwBnQsbvAWsZAX44oXNNvLHGqAOcoVxmjZiohstwQ7SqKnbR47akdNi+uleWD8+g6A==",
-      "dev": true,
      "license": "MIT",
      "funding": {
        "type": "opencollective",
@@ -5773,9 +5772,9 @@
      "license": "ISC"
    },
    "node_modules/bootstrap": {
-      "version": "4.6.2",
-      "resolved": "https://registry.npmjs.org/bootstrap/-/bootstrap-4.6.2.tgz",
-      "integrity": "sha512-51Bbp/Uxr9aTuy6ca/8FbFloBUJZLHwnhTcnjIeRn2suQWsWzcuJhGjKDB5eppVte/8oCdOL3VuwxvZDUggwGQ==",
+      "version": "5.3.5",
+      "resolved": "https://registry.npmjs.org/bootstrap/-/bootstrap-5.3.5.tgz",
+      "integrity": "sha512-ct1CHKtiobRimyGzmsSldEtM03E8fcEX4Tb3dGXz1V8faRwM50+vfHwTzOxB3IlKO7m+9vTH3s/3C6T2EAPeTA==",
      "funding": [
        {
          "type": "github",
@@ -5788,8 +5787,7 @@
      ],
      "license": "MIT",
      "peerDependencies": {
-        "jquery": "1.9.1 - 3",
-        "popper.js": "^1.16.1"
+        "@popperjs/core": "^2.11.8"
      }
    },
    "node_modules/bowser": {
@@ -10767,17 +10765,6 @@
        "node": ">=8"
      }
    },
-    "node_modules/popper.js": {
-      "version": "1.16.1",
-      "resolved": "https://registry.npmjs.org/popper.js/-/popper.js-1.16.1.tgz",
-      "integrity": "sha512-Wb4p1J4zyFTbM+u6WuO4XstYx4Ky9Cewe4DWrel7B0w6VVICvPwdOpotjzcf6eD8TsckVnIMNONQyPIUFOUbCQ==",
-      "deprecated": "You can find the new Popper v2 at @popperjs/core, this package is dedicated to the legacy v1",
-      "license": "MIT",
-      "funding": {
-        "type": "opencollective",
-        "url": "https://opencollective.com/popperjs"
-      }
-    },
    "node_modules/postcss": {
      "version": "8.5.3",
      "resolved": "https://registry.npmjs.org/postcss/-/postcss-8.5.3.tgz",
--- a/package.json
+++ b/package.json
@@ -31,7 +31,7 @@
    "@sentry/node": "^7.120.3",
    "@types/semver": "^7.7.0",
    "big-integer": "^1.6.52",
-    "bootstrap": "^4.6.2",
+    "bootstrap": "^5.3.5",
    "buffer": "^6.0.3",
    "chart.js": "^4.4.9",
    "clipboard": "^2.0.11",
@@ -57,7 +57,7 @@
    "nopt": "^8.1.0",
    "p-queue": "^8.1.0",
    "path-browserify": "^1.0.1",
-    "popper.js": "^1.16.1",
+    "@popperjs/core": "^2.11.8",
    "profanities": "^3.0.1",
    "prom-client": "^15.1.3",
    "pug": "^3.0.3",
--- a/static/bootstrap-utils.ts
+++ b/static/bootstrap-utils.ts
@@ -0,0 +1,471 @@
+// Copyright (c) 2025, Compiler Explorer Authors
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+//     * Redistributions of source code must retain the above copyright notice,
+//       this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above copyright
+//       notice, this list of conditions and the following disclaimer in the
+//       documentation and/or other materials provided with the distribution.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+
+/**
+ * TEMPORARY COMPATIBILITY LAYER
+ *
+ * This module provides utilities to help transition from Bootstrap 4's jQuery-based API
+ * to Bootstrap 5's vanilla JavaScript API. This is intended as a temporary solution
+ * during the migration from Bootstrap 4 to 5 and should be removed once the migration
+ * is complete.
+ *
+ * The goal is to minimize changes throughout the codebase by centralizing the Bootstrap
+ * API changes in this file, while still allowing for gradual migration to direct API calls.
+ *
+ * @deprecated This module should be removed after the Bootstrap 5 migration is complete.
+ */
+
+import $ from 'jquery';
+
+import 'bootstrap';
+import {Collapse, Dropdown, Modal, Popover, Tab, Toast, Tooltip} from 'bootstrap';
+
+// Private event listener tracking map
+const eventListenerMap = new WeakMap<HTMLElement, Map<string, EventListener>>();
+
+/**
+ * Helper method to get an HTMLElement from various input types
+ * @param elementOrSelector Element, jQuery object, or selector
+ * @returns HTMLElement or null
+ */
+function getElement(elementOrSelector: string | HTMLElement | JQuery): HTMLElement | null {
+    if (!elementOrSelector) return null;
+
+    if (typeof elementOrSelector === 'string') {
+        return document.querySelector(elementOrSelector as string);
+    }
+
+    if (elementOrSelector instanceof HTMLElement) {
+        return elementOrSelector;
+    }
+
+    if (elementOrSelector instanceof $) {
+        return (elementOrSelector as JQuery)[0] as HTMLElement;
+    }
+
+    return null;
+}
+
+/**
+ * Private helper that sets an event handler on a single DOM element
+ * Handles the removal of existing handlers and tracking of the new one
+ *
+ * @param domElement The DOM element to attach the event to
+ * @param eventName The event name (e.g., 'hidden.bs.modal', 'shown.bs.modal', 'click', etc.)
+ * @param handler The event handler function
+ */
+function setDomElementEventHandler(domElement: HTMLElement, eventName: string, handler: (event: Event) => void): void {
+    // Initialize nested map structure if needed
+    if (!eventListenerMap.has(domElement)) {
+        eventListenerMap.set(domElement, new Map());
+    }
+
+    const elementEvents = eventListenerMap.get(domElement)!;
+
+    // Remove existing handler if present
+    if (elementEvents.has(eventName)) {
+        const oldHandler = elementEvents.get(eventName)!;
+        domElement.removeEventListener(eventName, oldHandler);
+    }
+
+    // Store and add new handler
+    elementEvents.set(eventName, handler);
+    domElement.addEventListener(eventName, handler);
+}
+
+/**
+ * Registers an event handler on element(s), removing any previous handler for the same event
+ * Similar to jQuery's off().on() pattern
+ * Works with both single elements and jQuery collections with multiple elements
+ *
+ * @param element The element(s) or jQuery object to attach the event to
+ * @param eventName The event name (e.g., 'hidden.bs.modal', 'shown.bs.modal', 'click', etc.)
+ * @param handler The event handler function
+ */
+export function setElementEventHandler(
+    element: JQuery<HTMLElement> | HTMLElement,
+    eventName: string,
+    handler: (event: Event) => void,
+): void {
+    // If jQuery object with potentially multiple elements
+    if (!(element instanceof HTMLElement)) {
+        // Loop through all elements in the jQuery collection
+        element.each((_index, domElement) => {
+            setDomElementEventHandler(domElement, eventName, handler);
+        });
+        return;
+    }
+
+    // Otherwise it's a single DOM element
+    setDomElementEventHandler(element, eventName, handler);
+}
+
+/**
+ * Initialize a modal
+ * @param elementOrSelector Element or selector for the modal
+ * @param options Modal options
+ * @returns Modal instance
+ * @throws Error if the element cannot be found
+ */
+export function initModal(elementOrSelector: string | HTMLElement | JQuery, options?: Partial<Modal.Options>): Modal {
+    const element = getElement(elementOrSelector);
+    if (!element) throw new Error(`Failed to find element for modal: ${elementOrSelector}`);
+
+    return new Modal(element, options);
+}
+
+/**
+ * Initialize a modal if the element exists, returning null otherwise
+ * @param elementOrSelector Element or selector for the modal
+ * @param options Modal options
+ * @returns Modal instance or null if the element cannot be found
+ */
+export function initModalIfExists(
+    elementOrSelector: string | HTMLElement | JQuery,
+    options?: Partial<Modal.Options>,
+): Modal | null {
+    const element = getElement(elementOrSelector);
+    if (!element) return null;
+
+    return new Modal(element, options);
+}
+
+/**
+ * Get an existing modal instance for an element
+ * @param elementOrSelector Element or selector for the modal
+ * @returns Existing modal instance or null if not found
+ */
+export function getModalInstance(elementOrSelector: string | HTMLElement | JQuery): Modal | null {
+    const element = getElement(elementOrSelector);
+    if (!element) return null;
+
+    return Modal.getInstance(element);
+}
+
+/**
+ * Show a modal
+ * @param elementOrSelector Element or selector for the modal
+ * @param relatedTarget Optional related target element
+ */
+export function showModal(elementOrSelector: string | HTMLElement | JQuery, relatedTarget?: HTMLElement): void {
+    const element = getElement(elementOrSelector);
+    if (!element) return;
+
+    const modal = Modal.getInstance(element) || new Modal(element);
+    modal.show(relatedTarget);
+}
+
+/**
+ * Hide a modal
+ * @param elementOrSelector Element or selector for the modal
+ */
+export function hideModal(elementOrSelector: string | HTMLElement | JQuery): void {
+    const element = getElement(elementOrSelector);
+    if (!element) return;
+
+    const modal = Modal.getInstance(element);
+    if (modal) modal.hide();
+}
+
+/**
+ * Initialize a toast
+ * @param elementOrSelector Element or selector for the toast
+ * @param options Toast options
+ * @returns Toast instance
+ */
+export function initToast(elementOrSelector: string | HTMLElement | JQuery, options?: Partial<Toast.Options>): Toast {
+    const element = getElement(elementOrSelector);
+    if (!element) throw new Error(`Failed to find element for toast: ${elementOrSelector}`);
+
+    return new Toast(element, options);
+}
+
+/**
+ * Initialize a toast if the element exists
+ * @param elementOrSelector Element or selector for the toast
+ * @param options Toast options
+ * @returns Toast instance or null if element doesn't exist
+ */
+export function initToastIfExists(
+    elementOrSelector: string | HTMLElement | JQuery,
+    options?: Partial<Toast.Options>,
+): Toast | null {
+    const element = getElement(elementOrSelector);
+    if (!element) return null;
+
+    return new Toast(element, options);
+}
+
+/**
+ * Show a toast
+ * @param elementOrSelector Element or selector for the toast
+ */
+export function showToast(elementOrSelector: string | HTMLElement | JQuery): void {
+    const element = getElement(elementOrSelector);
+    if (!element) return;
+
+    const toast = Toast.getInstance(element) || new Toast(element);
+    toast.show();
+}
+
+/**
+ * Hide a toast
+ * @param elementOrSelector Element or selector for the toast
+ */
+export function hideToast(elementOrSelector: string | HTMLElement | JQuery): void {
+    const element = getElement(elementOrSelector);
+    if (!element) return;
+
+    const toast = Toast.getInstance(element);
+    if (toast) toast.hide();
+}
+
+/**
+ * Initialize a dropdown
+ * @param elementOrSelector Element or selector for the dropdown
+ * @param options Dropdown options
+ * @returns Dropdown instance
+ * @throws Error if the element cannot be found
+ */
+export function initDropdown(
+    elementOrSelector: string | HTMLElement | JQuery,
+    options?: Partial<Dropdown.Options>,
+): Dropdown {
+    const element = getElement(elementOrSelector);
+    if (!element) throw new Error(`Failed to find element for dropdown: ${elementOrSelector}`);
+
+    return new Dropdown(element, options);
+}
+
+/**
+ * Initialize a dropdown if the element exists, returning null otherwise
+ * @param elementOrSelector Element or selector for the dropdown
+ * @param options Dropdown options
+ * @returns Dropdown instance or null if the element cannot be found
+ */
+export function initDropdownIfExists(
+    elementOrSelector: string | HTMLElement | JQuery,
+    options?: Partial<Dropdown.Options>,
+): Dropdown | null {
+    const element = getElement(elementOrSelector);
+    if (!element) return null;
+
+    return new Dropdown(element, options);
+}
+
+/**
+ * Get an existing dropdown instance for an element
+ * @param elementOrSelector Element or selector for the dropdown
+ * @returns Existing dropdown instance or null if not found
+ */
+export function getDropdownInstance(elementOrSelector: string | HTMLElement | JQuery): Dropdown | null {
+    const element = getElement(elementOrSelector);
+    if (!element) return null;
+
+    return Dropdown.getInstance(element);
+}
+
+/**
+ * Show a dropdown
+ * @param elementOrSelector Element or selector for the dropdown
+ */
+export function showDropdown(elementOrSelector: string | HTMLElement | JQuery): void {
+    const element = getElement(elementOrSelector);
+    if (!element) return;
+
+    const dropdown = Dropdown.getInstance(element) || new Dropdown(element);
+    dropdown.show();
+}
+
+/**
+ * Hide a dropdown
+ * @param elementOrSelector Element or selector for the dropdown
+ */
+export function hideDropdown(elementOrSelector: string | HTMLElement | JQuery): void {
+    const element = getElement(elementOrSelector);
+    if (!element) return;
+
+    const dropdown = Dropdown.getInstance(element);
+    if (dropdown) dropdown.hide();
+}
+
+/**
+ * Initialize a tooltip
+ * @param elementOrSelector Element or selector for the tooltip
+ * @param options Tooltip options
+ * @returns Tooltip instance
+ */
+export function initTooltip(
+    elementOrSelector: string | HTMLElement | JQuery,
+    options?: Partial<Tooltip.Options>,
+): Tooltip {
+    const element = getElement(elementOrSelector);
+    if (!element) throw new Error(`Failed to find element for tooltip: ${elementOrSelector}`);
+
+    return new Tooltip(element, options);
+}
+
+/**
+ * Initialize a tooltip if the element exists
+ * @param elementOrSelector Element or selector for the tooltip
+ * @param options Tooltip options
+ * @returns Tooltip instance or null if element doesn't exist
+ */
+export function initTooltipIfExists(
+    elementOrSelector: string | HTMLElement | JQuery,
+    options?: Partial<Tooltip.Options>,
+): Tooltip | null {
+    const element = getElement(elementOrSelector);
+    if (!element) return null;
+
+    return new Tooltip(element, options);
+}
+
+/**
+ * Initialize a popover
+ * @param elementOrSelector Element or selector for the popover
+ * @param options Popover options
+ * @returns Popover instance
+ * @throws Error if the element cannot be found
+ */
+export function initPopover(
+    elementOrSelector: string | HTMLElement | JQuery,
+    options?: Partial<Popover.Options>,
+): Popover {
+    const element = getElement(elementOrSelector);
+    if (!element) throw new Error(`Failed to find element for popover: ${elementOrSelector}`);
+
+    return new Popover(element, options);
+}
+
+/**
+ * Initialize a popover if the element exists, returning null otherwise
+ * @param elementOrSelector Element or selector for the popover
+ * @param options Popover options
+ * @returns Popover instance or null if the element cannot be found
+ */
+export function initPopoverIfExists(
+    elementOrSelector: string | HTMLElement | JQuery,
+    options?: Partial<Popover.Options>,
+): Popover | null {
+    const element = getElement(elementOrSelector);
+    if (!element) return null;
+
+    return new Popover(element, options);
+}
+
+/**
+ * Get an existing popover instance for an element
+ * @param elementOrSelector Element or selector for the popover
+ * @returns Existing popover instance or null if not found
+ */
+export function getPopoverInstance(elementOrSelector: string | HTMLElement | JQuery): Popover | null {
+    const element = getElement(elementOrSelector);
+    if (!element) return null;
+
+    return Popover.getInstance(element);
+}
+
+/**
+ * Initialize a tab
+ * @param elementOrSelector Element or selector for the tab
+ * @returns Tab instance
+ */
+export function initTab(elementOrSelector: string | HTMLElement | JQuery): Tab {
+    const element = getElement(elementOrSelector);
+    if (!element) throw new Error(`Failed to find element for tab: ${elementOrSelector}`);
+
+    return new Tab(element);
+}
+
+/**
+ * Initialize a tab if the element exists
+ * @param elementOrSelector Element or selector for the tab
+ * @returns Tab instance or null if element doesn't exist
+ */
+export function initTabIfExists(elementOrSelector: string | HTMLElement | JQuery): Tab | null {
+    const element = getElement(elementOrSelector);
+    if (!element) return null;
+
+    return new Tab(element);
+}
+
+/**
+ * Initialize a collapse
+ * @param elementOrSelector Element or selector for the collapse
+ * @param options Collapse options
+ * @returns Collapse instance
+ */
+export function initCollapse(
+    elementOrSelector: string | HTMLElement | JQuery,
+    options?: Partial<Collapse.Options>,
+): Collapse {
+    const element = getElement(elementOrSelector);
+    if (!element) throw new Error(`Failed to find element for collapse: ${elementOrSelector}`);
+
+    return new Collapse(element, options);
+}
+
+/**
+ * Initialize a collapse if the element exists
+ * @param elementOrSelector Element or selector for the collapse
+ * @param options Collapse options
+ * @returns Collapse instance or null if element doesn't exist
+ */
+export function initCollapseIfExists(
+    elementOrSelector: string | HTMLElement | JQuery,
+    options?: Partial<Collapse.Options>,
+): Collapse | null {
+    const element = getElement(elementOrSelector);
+    if (!element) return null;
+
+    return new Collapse(element, options);
+}
+
+/**
+ * Hide an existing popover if it exists
+ * @param elementOrSelector Element or selector for the popover
+ */
+export function hidePopover(elementOrSelector: string | HTMLElement | JQuery): void {
+    const popover = getPopoverInstance(elementOrSelector);
+    if (popover) popover.hide();
+}
+
+/**
+ * Show an existing popover if it exists
+ * @param elementOrSelector Element or selector for the popover
+ */
+export function showPopover(elementOrSelector: string | HTMLElement | JQuery): void {
+    const popover = getPopoverInstance(elementOrSelector);
+    if (popover) popover.show();
+}
+
+/**
+ * Show an existing modal if it exists (uses existing instance only)
+ * @param elementOrSelector Element or selector for the modal
+ */
+export function showModalIfExists(elementOrSelector: string | HTMLElement | JQuery): void {
+    const modal = getModalInstance(elementOrSelector);
+    if (modal) modal.show();
+}
--- a/static/main.ts
+++ b/static/main.ts
@@ -28,7 +28,7 @@ import {SentryCapture, SetupSentry, setSentryLayout} from './sentry.js';
 SetupSentry();

 import 'whatwg-fetch';
-import 'popper.js';
+import '@popperjs/core';
 import 'bootstrap';

 import $ from 'jquery';
@@ -62,6 +62,7 @@ import {ComponentConfig, EmptyCompilerState, StateWithId, StateWithLanguage} fro
 import {CompilerExplorerOptions} from './global.js';

 import * as utils from '../shared/common-utils.js';
+import * as BootstrapUtils from './bootstrap-utils.js';
 import {ParseFiltersAndOutputOptions} from './features/filters.interfaces.js';
 import {localStorage, sessionThenLocalStorage} from './local.js';
 import {Printerinator} from './print-view.js';
@@ -79,7 +80,7 @@ if (!window.PRODUCTION && !options.embedded) {
 //css
 require('bootstrap/dist/css/bootstrap.min.css');
 require('golden-layout/src/css/goldenlayout-base.css');
-require('tom-select/dist/css/tom-select.bootstrap4.css');
+require('tom-select/dist/css/tom-select.bootstrap5.css');
 require('./styles/colours.scss');
 require('./styles/explorer.scss');

@@ -225,7 +226,7 @@ function setupButtons(options: CompilerExplorerOptions, hub: Hub) {
            window.location.reload();
        });

-        $('#history').modal();
+        BootstrapUtils.showModal('#history');
    });

    $('#ui-apply-default-font-scale').on('click', () => {
@@ -530,7 +531,7 @@ function initShortlinkInfoButton() {
        buttonText.html('');

        const button = $('.shortlinkInfo');
-        button.popover({
+        BootstrapUtils.initPopover(button, {
            html: true,
            title: 'Link created',
            content: formatISODate(dt, true),
@@ -677,11 +678,13 @@ function start() {
        setupButtons(options, hub);
    }

-    const addDropdown = $('#addDropdown');
-
    function setupAdd<C>(thing: JQuery, func: () => ComponentConfig<C>) {
        (layout.createDragSource(thing, func as any) as any)._dragListener.on('dragStart', () => {
-            addDropdown.dropdown('toggle');
+            const addDropdown = unwrap(
+                BootstrapUtils.getDropdownInstance('#addDropdown'),
+                'Dropdown instance not found for #addDropdown',
+            );
+            addDropdown.toggle();
        });

        thing.on('click', () => {
--- a/static/motd.ts
+++ b/static/motd.ts
@@ -30,7 +30,7 @@ function ensureShownMessage(message: string, motdNode: JQuery) {
    motdNode.find('.content').html(message);
    motdNode.removeClass('d-none');
    motdNode
-        .find('.close')
+        .find('.btn-close')
        .on('click', () => {
            motdNode.addClass('d-none');
        })
--- a/static/noscript.ts
+++ b/static/noscript.ts
@@ -25,8 +25,8 @@
 // This jQuery import needs to be here, because noscript.ts is a different entrypoint than the rest of the code.
 // See webpack.config.esm.ts -> entry for more details.
 import $ from 'jquery';
+import '@popperjs/core';
 import 'bootstrap';
-import 'popper.js';

 import {Toggles} from './widgets/toggles.js';
 import './styles/noscript.scss';
--- a/static/panes/cfg-view.ts
+++ b/static/panes/cfg-view.ts
@@ -26,6 +26,7 @@ import * as fileSaver from 'file-saver';
 import $ from 'jquery';
 import * as monaco from 'monaco-editor';
 import _ from 'underscore';
+import * as BootstrapUtils from '../bootstrap-utils.js';
 import {Pane} from './pane.js';

 import {Container} from 'golden-layout';
@@ -281,7 +282,9 @@ export class Cfg extends Pane<CfgState> {
            if (this.tooltipOpen) {
                if (!e.target.classList.contains('fold') && $(e.target).parents('.popover.in').length === 0) {
                    this.tooltipOpen = false;
-                    $('.fold').popover('hide');
+                    $('.fold').each((_, element) => {
+                        BootstrapUtils.hidePopover(element);
+                    });
                }
            }
        });
@@ -389,25 +392,27 @@ export class Cfg extends Pane<CfgState> {
                }" aria-describedby="wtf">&#8943;</span>`;
            }
            div.innerHTML = lines.join('<br/>');
-            for (const fold of div.getElementsByClassName('fold')) {
-                $(fold)
-                    .popover({
-                        content: unwrap(fold.getAttribute('data-extra')),
-                        html: true,
-                        placement: 'top',
-                        template:
-                            '<div class="popover cfg-fold-popover" role="tooltip">' +
-                            '<div class="arrow"></div>' +
-                            '<h3 class="popover-header"></h3>' +
-                            '<div class="popover-body"></div>' +
-                            '</div>',
-                    })
-                    .on('show.bs.popover', () => {
-                        this.tooltipOpen = true;
-                    })
-                    .on('hide.bs.popover', () => {
-                        this.tooltipOpen = false;
-                    });
+            for (const foldElement of div.getElementsByClassName('fold')) {
+                const fold = foldElement as HTMLElement;
+
+                BootstrapUtils.initPopover(fold, {
+                    content: unwrap(fold.getAttribute('data-extra')),
+                    html: true,
+                    placement: 'top',
+                    template:
+                        '<div class="popover cfg-fold-popover" role="tooltip">' +
+                        '<div class="arrow"></div>' +
+                        '<h3 class="popover-header"></h3>' +
+                        '<div class="popover-body"></div>' +
+                        '</div>',
+                });
+
+                BootstrapUtils.setElementEventHandler(fold, 'show.bs.popover', () => {
+                    this.tooltipOpen = true;
+                });
+                BootstrapUtils.setElementEventHandler(fold, 'hide.bs.popover', () => {
+                    this.tooltipOpen = false;
+                });
            }
            // So because this is async there's a race condition here if you rapidly switch functions.
            // This can be triggered by loading an example program. Because the fix going to be tricky I'll defer
@@ -500,7 +505,11 @@ export class Cfg extends Pane<CfgState> {
    // Display the cfg for the specified function if it exists
    // This function sets this.state.selectedFunction if the input is non-null and valid
    async selectFunction(name: string | null) {
-        $('.fold').popover('dispose');
+        $('.fold').each((_, element) => {
+            const popover = BootstrapUtils.getPopoverInstance(element);
+            if (popover) popover.dispose();
+            // We need to dispose here, not just hide
+        });
        this.blockContainer.innerHTML = '';
        this.svg.innerHTML = '';
        this.estimatedPNGSize.innerHTML = '';
@@ -669,7 +678,9 @@ export class Cfg extends Pane<CfgState> {
            const topBarHeight = utils.updateAndCalcTopBarHeight(this.domRoot, this.topBar, this.hideable);
            this.graphContainer.style.width = `${unwrap(this.domRoot.width())}px`;
            this.graphContainer.style.height = `${unwrap(this.domRoot.height()) - topBarHeight}px`;
-            $('.fold').popover('hide');
+            $('.fold').each((_, element) => {
+                BootstrapUtils.hidePopover(element);
+            });
        });
    }

--- a/static/panes/compiler.ts
+++ b/static/panes/compiler.ts
@@ -42,6 +42,7 @@ import {
 import {CompilerInfo} from '../../types/compiler.interfaces.js';
 import {ResultLine} from '../../types/resultline/resultline.interfaces.js';
 import {getAssemblyDocumentation} from '../api/api.js';
+import * as BootstrapUtils from '../bootstrap-utils.js';
 import * as codeLensHandler from '../codelens-handler.js';
 import * as colour from '../colour.js';
 import {OptPipelineBackendOptions} from '../compilation/opt-pipeline-output.interfaces.js';
@@ -678,7 +679,7 @@ export class Compiler extends MonacoPane<monaco.editor.IStandaloneCodeEditor, Co

        const newPaneDropdown = this.domRoot.find('.new-pane-dropdown');
        const hidePaneAdder = () => {
-            newPaneDropdown.dropdown('hide');
+            BootstrapUtils.hideDropdown(newPaneDropdown);
        };

        // Note that the .d.ts file lies in more than 1 way!
@@ -729,7 +730,7 @@ export class Compiler extends MonacoPane<monaco.editor.IStandaloneCodeEditor, Co
                .createDragSource(this.flagsButton, createFlagsView as any)

                // @ts-ignore
-                ._dragListener.on('dragStart', () => popularArgumentsMenu.dropdown('hide'));
+                ._dragListener.on('dragStart', () => BootstrapUtils.hideDropdown(popularArgumentsMenu));

            this.flagsButton.on('click', () => {
                const insertPoint =
@@ -1868,7 +1869,7 @@ export class Compiler extends MonacoPane<monaco.editor.IStandaloneCodeEditor, Co
                dismissTime: 10000,
                onBeforeShow: elem => {
                    elem.find('#miracle_emulink').on('click', () => {
-                        dialog.modal();
+                        BootstrapUtils.showModal(dialog);

                        const miracleMenuFrame = dialog.find('#miracleemuframe')[0];
                        assert(miracleMenuFrame instanceof HTMLIFrameElement);
@@ -1896,7 +1897,7 @@ export class Compiler extends MonacoPane<monaco.editor.IStandaloneCodeEditor, Co
                dismissTime: 10000,
                onBeforeShow: elem => {
                    elem.find('#jsspeccy_emulink').on('click', () => {
-                        dialog.modal();
+                        BootstrapUtils.showModal(dialog);

                        const speccyemuframe = dialog.find('#speccyemuframe')[0];
                        assert(speccyemuframe instanceof HTMLIFrameElement);
@@ -1923,7 +1924,7 @@ export class Compiler extends MonacoPane<monaco.editor.IStandaloneCodeEditor, Co
                dismissTime: 10000,
                onBeforeShow: elem => {
                    elem.find('#emulink').on('click', () => {
-                        dialog.modal();
+                        BootstrapUtils.showModal(dialog);

                        const jsbeebemuframe = dialog.find('#jsbeebemuframe')[0];
                        assert(jsbeebemuframe instanceof HTMLIFrameElement);
@@ -1950,7 +1951,7 @@ export class Compiler extends MonacoPane<monaco.editor.IStandaloneCodeEditor, Co
                dismissTime: 10000,
                onBeforeShow: elem => {
                    elem.find('#emulink').on('click', () => {
-                        dialog.modal();
+                        BootstrapUtils.showModal(dialog);

                        const jsnesemuframe = dialog.find('#jsnesemuframe')[0];
                        assert(jsnesemuframe instanceof HTMLIFrameElement);
@@ -2683,7 +2684,7 @@ export class Compiler extends MonacoPane<monaco.editor.IStandaloneCodeEditor, Co
    initToolButtons(): void {
        this.toolsMenu = this.domRoot.find('.new-tool-dropdown');
        const hideToolDropdown = () => {
-            this.toolsMenu?.dropdown('hide');
+            if (this.toolsMenu) BootstrapUtils.hideDropdown(this.toolsMenu);
        };
        this.toolsMenu.empty();

@@ -3053,14 +3054,14 @@ export class Compiler extends MonacoPane<monaco.editor.IStandaloneCodeEditor, Co
                this.prependOptions.has(target as unknown as Element).length === 0 &&
                target.closest('.popover').length === 0
            )
-                this.prependOptions.popover('hide');
+                BootstrapUtils.hidePopover(this.prependOptions);

            if (
                !target.is(this.fullCompilerName) &&
                this.fullCompilerName.has(target as unknown as Element).length === 0 &&
                target.closest('.popover').length === 0
            )
-                this.fullCompilerName.popover('hide');
+                BootstrapUtils.hidePopover(this.fullCompilerName);
        });
    }

@@ -3104,7 +3105,7 @@ export class Compiler extends MonacoPane<monaco.editor.IStandaloneCodeEditor, Co
        // Dismiss the popover on escape.
        $(document).on('keyup.editable', e => {
            if (e.which === 27) {
-                this.libsButton.popover('hide');
+                BootstrapUtils.hidePopover(this.libsButton);
            }
        });

@@ -3118,7 +3119,7 @@ export class Compiler extends MonacoPane<monaco.editor.IStandaloneCodeEditor, Co
                elem.has(target as unknown as Element).length === 0 &&
                target.closest('.popover').length === 0
            ) {
-                elem.popover('hide');
+                BootstrapUtils.hidePopover(elem);
            }
        });
    }
@@ -3460,8 +3461,13 @@ export class Compiler extends MonacoPane<monaco.editor.IStandaloneCodeEditor, Co
    setCompilationOptionsPopover(content: string | null, warnings: string[]): void {
        const infoLine =
            '<div class="compiler-arg-warning info">You can configure icon animations in Settings>Compilation</div>\n';
-        this.prependOptions.popover('dispose');
-        this.prependOptions.popover({
+
+        // Dispose any existing popover
+        const existingPopover = BootstrapUtils.getPopoverInstance(this.prependOptions);
+        if (existingPopover) existingPopover.dispose();
+
+        // Create new popover
+        BootstrapUtils.initPopover(this.prependOptions, {
            content:
                warnings.map(w => `<div class="compiler-arg-warning">${w}</div>`).join('\n') +
                '\n' +
--- a/static/panes/conformance-view.ts
+++ b/static/panes/conformance-view.ts
@@ -29,6 +29,7 @@ import {escapeHTML, unique} from '../../shared/common-utils.js';
 import {CompilationResult} from '../../types/compilation/compilation.interfaces.js';
 import {CompilerInfo} from '../../types/compiler.interfaces.js';
 import {unwrapString} from '../assert.js';
+import * as BootstrapUtils from '../bootstrap-utils.js';
 import {CompilationStatus} from '../compiler-service.interfaces.js';
 import {CompilerService} from '../compiler-service.js';
 import * as Components from '../components.js';
@@ -100,7 +101,7 @@ export class Conformance extends Pane<ConformanceViewState> {
        // Dismiss the popover on escape.
        $(document).on('keyup.editable', e => {
            if (e.which === 27) {
-                this.libsButton.popover('hide');
+                BootstrapUtils.hidePopover(this.libsButton);
            }
        });

@@ -114,7 +115,7 @@ export class Conformance extends Pane<ConformanceViewState> {
                elem.has(target as unknown as Element).length === 0 &&
                target.closest('.popover').length === 0
            ) {
-                elem.popover('hide');
+                BootstrapUtils.hidePopover(elem);
            }
        });
    }
@@ -150,7 +151,7 @@ export class Conformance extends Pane<ConformanceViewState> {
        this.conformanceContentRoot = this.domRoot.find('.conformance-wrapper');
        this.selectorList = this.domRoot.find('.compiler-list');
        this.addCompilerButton = this.domRoot.find('.add-compiler');
-        this.selectorTemplate = $('#compiler-selector').find('.form-row');
+        this.selectorTemplate = $('#compiler-selector').find('.row');
        this.topBar = this.domRoot.find('.top-bar');
        this.libsButton = this.topBar.find('.show-libs');
        this.hideable = this.domRoot.find('.hideable');
@@ -225,15 +226,11 @@ export class Conformance extends Pane<ConformanceViewState> {
            .on('change', onOptionsChange)
            .on('keyup', onOptionsChange);

-        newSelector
-            .find('.close')
-            .not('.extract-compiler')
-            .not('.copy-compiler')
-            .on('click', () => {
-                this.removeCompilerPicker(newCompilerEntry);
-            });
+        newSelector.find('.close-compiler').on('click', () => {
+            this.removeCompilerPicker(newCompilerEntry);
+        });

-        newSelector.find('.close.copy-compiler').on('click', () => {
+        newSelector.find('.copy-compiler').on('click', () => {
            const config: AddCompilerPickerConfig = {
                compilerId: newCompilerEntry.picker?.lastCompilerId ?? '',
                options: newCompilerEntry.optionsField?.val() || '',
@@ -301,15 +298,19 @@ export class Conformance extends Pane<ConformanceViewState> {
    ): void {}

    setCompilationOptionsPopover(element: JQuery<HTMLElement> | null, content: string): void {
-        element?.popover('dispose');
-        element?.popover({
-            content: content || 'No options in use',
-            template:
-                '<div class="popover' +
-                (content ? ' compiler-options-popover' : '') +
-                '" role="tooltip"><div class="arrow"></div>' +
-                '<h3 class="popover-header"></h3><div class="popover-body"></div></div>',
-        });
+        if (element) {
+            const existingPopover = BootstrapUtils.getPopoverInstance(element);
+            if (existingPopover) existingPopover.dispose();
+
+            BootstrapUtils.initPopover(element, {
+                content: content || 'No options in use',
+                template:
+                    '<div class="popover' +
+                    (content ? ' compiler-options-popover' : '') +
+                    '" role="tooltip"><div class="arrow"></div>' +
+                    '<h3 class="popover-header"></h3><div class="popover-body"></div></div>',
+            });
+        }
    }

    removeCompilerPicker(compilerEntry: CompilerEntry): void {
--- a/static/panes/diff.ts
+++ b/static/panes/diff.ts
@@ -482,10 +482,7 @@ export class Diff extends MonacoPane<monaco.editor.IStandaloneDiffEditor, DiffSt
    ) {
        if (!compiler) return;
        options = options || '';
-        let name = compiler.name + ' ' + options;
-        // TODO: tomselect doesn't play nicely with CSS tricks for truncation; this is the best I can do
-        const maxLength = 30;
-        if (name.length > maxLength - 3) name = name.substring(0, maxLength - 3) + '...';
+        const name = compiler.name + ' ' + options;
        this.compilers[id] = {
            id: id,
            name: name,
--- a/static/panes/editor.ts
+++ b/static/panes/editor.ts
@@ -29,6 +29,7 @@ import * as monaco from 'monaco-editor';
 import * as monacoVim from 'monaco-vim';
 import TomSelect from 'tom-select';
 import _ from 'underscore';
+import * as BootstrapUtils from '../bootstrap-utils.js';
 import * as colour from '../colour.js';
 import * as Components from '../components.js';
 import * as monacoConfig from '../monaco-config.js';
@@ -472,7 +473,7 @@ export class Editor extends MonacoPane<monaco.editor.IStandaloneCodeEditor, Edit
    }

    enableVim(): void {
-        const statusElem = this.domRoot.find('#v-status')[0];
+        const statusElem = this.domRoot.find('.v-status')[0];
        const vimMode = monacoVim.initVimMode(this.editor, statusElem);
        this.vimMode = vimMode;
        this.vimFlag.prop('class', 'btn btn-info');
@@ -481,7 +482,7 @@ export class Editor extends MonacoPane<monaco.editor.IStandaloneCodeEditor, Edit

    disableVim(): void {
        this.vimMode.dispose();
-        this.domRoot.find('#v-status').html('');
+        this.domRoot.find('.v-status').html('');
        this.vimFlag.prop('class', 'btn btn-light');
        (this.editor as any).vimInUse = false;
    }
@@ -520,8 +521,8 @@ export class Editor extends MonacoPane<monaco.editor.IStandaloneCodeEditor, Edit
        this.addExecutorButton = this.domRoot.find('.btn.add-executor');
        this.conformanceViewerButton = this.domRoot.find('.btn.conformance');
        const addEditorButton = this.domRoot.find('.btn.add-editor');
-        const toggleVimButton = this.domRoot.find('#vim-flag');
-        this.vimFlag = this.domRoot.find('#vim-flag');
+        const toggleVimButton = this.domRoot.find('.vim-flag');
+        this.vimFlag = this.domRoot.find('.vim-flag');
        toggleVimButton.on('click', () => {
            if ((this.editor as any).vimInUse) {
                this.disableVim();
@@ -541,7 +542,7 @@ export class Editor extends MonacoPane<monaco.editor.IStandaloneCodeEditor, Edit
        });

        this.languageInfoButton = this.domRoot.find('.language-info');
-        this.languageInfoButton.popover({});
+        BootstrapUtils.initPopover(this.languageInfoButton);
        this.languageBtn = this.domRoot.find('.change-language');
        const changeLanguageButton = this.languageBtn[0];
        assert(changeLanguageButton instanceof HTMLSelectElement);
@@ -598,7 +599,10 @@ export class Editor extends MonacoPane<monaco.editor.IStandaloneCodeEditor, Edit
                .createDragSource(dragSource, dragConfig)
                // @ts-expect-error: createDragSource returns not void
                ._dragListener.on('dragStart', () => {
-                    paneAdderDropdown.dropdown('toggle');
+                    const dropdown = BootstrapUtils.getDropdownInstance(paneAdderDropdown);
+                    if (dropdown) {
+                        dropdown.toggle();
+                    }
                });

            dragSource.on('click', () => {
@@ -1921,7 +1925,7 @@ export class Editor extends MonacoPane<monaco.editor.IStandaloneCodeEditor, Edit
    ): string {
        let result =
            '<div class="d-flex" style="align-items: center">' +
-            '<div class="mr-1 d-flex" style="align-items: center">' +
+            '<div class="me-1 d-flex" style="align-items: center">' +
            '<img src="' +
            (data.logoData ? data.logoData : '') +
            '" class="' +
@@ -1961,9 +1965,12 @@ export class Editor extends MonacoPane<monaco.editor.IStandaloneCodeEditor, Edit
    onCompiler(compilerId: number, compiler: unknown, options: string, editorId: number, treeId: number): void {}

    updateLanguageTooltip() {
-        this.languageInfoButton.popover('dispose');
+        // Dispose existing popover instance
+        const existingPopover = BootstrapUtils.getPopoverInstance(this.languageInfoButton);
+        if (existingPopover) existingPopover.dispose();
+
        if (this.currentLanguage?.tooltip) {
-            this.languageInfoButton.popover({
+            BootstrapUtils.initPopover(this.languageInfoButton, {
                title: 'More info about this language',
                content: this.currentLanguage.tooltip,
                container: 'body',
--- a/static/panes/executor.ts
+++ b/static/panes/executor.ts
@@ -38,6 +38,7 @@ import {Language} from '../../types/languages.interfaces.js';
 import {ResultLine} from '../../types/resultline/resultline.interfaces.js';
 import {Artifact, ArtifactType} from '../../types/tool.interfaces.js';
 import {Filter as AnsiToHtml} from '../ansi-to-html.js';
+import * as BootstrapUtils from '../bootstrap-utils.js';
 import {CompilationStatus as CompilerServiceCompilationStatus} from '../compiler-service.interfaces.js';
 import {CompilerService} from '../compiler-service.js';
 import {ICompilerShared} from '../compiler-shared.interfaces.js';
@@ -799,15 +800,19 @@ export class Executor extends Pane<ExecutorState> {
                !target.is(this.prependOptions) &&
                this.prependOptions.has(target as any).length === 0 &&
                target.closest('.popover').length === 0
-            )
-                this.prependOptions.popover('hide');
+            ) {
+                const popover = BootstrapUtils.getPopoverInstance(this.prependOptions);
+                if (popover) popover.hide();
+            }

            if (
                !target.is(this.fullCompilerName) &&
                this.fullCompilerName.has(target as any).length === 0 &&
                target.closest('.popover').length === 0
-            )
-                this.fullCompilerName.popover('hide');
+            ) {
+                const popover = BootstrapUtils.getPopoverInstance(this.fullCompilerName);
+                if (popover) popover.hide();
+            }
        });

        this.optionsField.val(this.options);
@@ -963,7 +968,8 @@ export class Executor extends Pane<ExecutorState> {
        // Dismiss the popover on escape.
        $(document).on('keyup.editable', e => {
            if (e.which === 27) {
-                this.libsButton.popover('hide');
+                const popover = BootstrapUtils.getPopoverInstance(this.libsButton);
+                if (popover) popover.hide();
            }
        });

@@ -997,7 +1003,8 @@ export class Executor extends Pane<ExecutorState> {
            const elem = this.libsButton;
            const target = $(e.target);
            if (!target.is(elem) && elem.has(target as any).length === 0 && target.closest('.popover').length === 0) {
-                elem.popover('hide');
+                const popover = BootstrapUtils.getPopoverInstance(elem);
+                if (popover) popover.hide();
            }
        });

@@ -1186,8 +1193,12 @@ export class Executor extends Pane<ExecutorState> {
    }

    setCompilationOptionsPopover(content: string | null) {
-        this.prependOptions.popover('dispose');
-        this.prependOptions.popover({
+        // Dispose of existing popover
+        const existingPopover = BootstrapUtils.getPopoverInstance(this.prependOptions);
+        if (existingPopover) existingPopover.dispose();
+
+        // Initialize new popover
+        BootstrapUtils.initPopover(this.prependOptions, {
            content: content || 'No options in use',
            template:
                '<div class="popover' +
--- a/static/panes/tree.ts
+++ b/static/panes/tree.ts
@@ -29,6 +29,7 @@ import TomSelect from 'tom-select';
 import _ from 'underscore';
 import {escapeHTML} from '../../shared/common-utils.js';
 import {assert, unwrap, unwrapString} from '../assert.js';
+import * as BootstrapUtils from '../bootstrap-utils.js';
 import * as Components from '../components.js';
 import {EventHub} from '../event-hub.js';
 import {Hub} from '../hub.js';
@@ -448,7 +449,11 @@ export class Tree {
        (this.container.layoutManager.createDragSource(dragSource, dragConfig.bind(this)) as any)._dragListener.on(
            'dragStart',
            () => {
-                this.domRoot.find('.add-pane').dropdown('toggle');
+                const dropdown = this.domRoot.find('.add-pane');
+                const dropdownInstance = BootstrapUtils.getDropdownInstance(dropdown);
+                if (dropdownInstance) {
+                    dropdownInstance.toggle();
+                }
            },
        );

--- a/static/real-dark.ts
+++ b/static/real-dark.ts
@@ -48,7 +48,7 @@ export function setupRealDark(hub: Hub) {
            $('#settings .theme').val('real-dark').trigger('change');
        }
    });
-    $('#true-dark .content .close').on('click', e => {
+    $('#true-dark .content .dark-close').on('click', e => {
        local.localStorage.set(localKey, 'hidden');
        toggleButton();
        toggleOverlay();
--- a/static/sharing.ts
+++ b/static/sharing.ts
@@ -22,18 +22,20 @@
 // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 // POSSIBILITY OF SUCH DAMAGE.

+import {Modal, Tooltip} from 'bootstrap';
 import ClipboardJS from 'clipboard';
 import GoldenLayout from 'golden-layout';
 import $ from 'jquery';
 import _ from 'underscore';
+import {unwrap} from './assert.js';
+import * as BootstrapUtils from './bootstrap-utils.js';
 import {sessionThenLocalStorage} from './local.js';
 import {options} from './options.js';
 import * as url from './url.js';

-import ClickEvent = JQuery.ClickEvent;
-import TriggeredEvent = JQuery.TriggeredEvent;
 import {SentryCapture} from './sentry.js';
 import {Settings, SiteSettings} from './settings.js';
+import ClickEvent = JQuery.ClickEvent;

 const cloneDeep = require('lodash.clonedeep');

@@ -87,24 +89,31 @@ export class Sharing {
    private layout: GoldenLayout;
    private lastState: any;

-    private share: JQuery;
-    private shareShort: JQuery;
-    private shareFull: JQuery;
-    private shareEmbed: JQuery;
+    private readonly share: JQuery;
+    private readonly shareTooltipTarget: JQuery;
+    private readonly shareShort: JQuery;
+    private readonly shareFull: JQuery;
+    private readonly shareEmbed: JQuery;

    private settings: SiteSettings;

    private clippyButton: ClipboardJS | null;
+    private readonly shareLinkDialog: HTMLElement;

    constructor(layout: any) {
        this.layout = layout;
        this.lastState = null;
+        this.shareLinkDialog = unwrap(document.getElementById('sharelinkdialog'), 'Share modal element not found');

        this.share = $('#share');
+        this.shareTooltipTarget = $('#share-tooltip-target');
        this.shareShort = $('#shareShort');
        this.shareFull = $('#shareFull');
        this.shareEmbed = $('#shareEmbed');

+        [this.shareShort, this.shareFull, this.shareEmbed].forEach(el =>
+            el.on('click', e => BootstrapUtils.showModal(this.shareLinkDialog, e.currentTarget)),
+        );
        this.settings = Settings.getStoredSettings();

        this.clippyButton = null;
@@ -122,9 +131,9 @@ export class Sharing {
        });
        this.layout.on('stateChanged', this.onStateChanged.bind(this));

-        $('#sharelinkdialog')
-            .on('show.bs.modal', this.onOpenModalPane.bind(this))
-            .on('hidden.bs.modal', this.onCloseModalPane.bind(this));
+        BootstrapUtils.initModal(this.shareLinkDialog);
+        this.shareLinkDialog.addEventListener('show.bs.modal', this.onOpenModalPane.bind(this));
+        this.shareLinkDialog.addEventListener('hidden.bs.modal', this.onCloseModalPane.bind(this));

        this.layout.eventHub.on('settingsChange', (newSettings: SiteSettings) => {
            this.settings = newSettings;
@@ -176,11 +185,16 @@ export class Sharing {
        }
    }

-    private onOpenModalPane(event: TriggeredEvent<HTMLElement, undefined, HTMLElement, HTMLElement>): void {
-        // @ts-ignore The property is added by bootstrap
-        const button = $(event.relatedTarget);
-        const currentBind = Sharing.bindToLinkType(button.data('bind'));
-        const modal = $(event.currentTarget);
+    private onOpenModalPane(event: Event): void {
+        const modalEvent = event as Modal.Event;
+        if (!modalEvent.relatedTarget) {
+            throw new Error('No relatedTarget found in modal event');
+        }
+
+        const button = $(modalEvent.relatedTarget);
+        const bindStr = button.data('bind') as string;
+        const currentBind = Sharing.bindToLinkType(bindStr);
+        const modal = $(event.currentTarget as HTMLElement);
        const socialSharingElements = modal.find('.socialsharing');
        const permalink = modal.find('.permalink');
        const embedsettings = modal.find('#embedsettings');
@@ -262,15 +276,16 @@ export class Sharing {
        }
    }

-    private onClipButtonPressed(event: ClickEvent, type: LinkType): void {
+    private onClipButtonPressed(event: ClickEvent, type: LinkType): boolean {
        // Don't let the modal show up.
-        // We need this because the button is a child of the dropdown-item with a data-toggle=modal
+        // We need this because the button is a child of the dropdown-item with a data-bs-toggle=modal
        if (Sharing.isNavigatorClipboardAvailable()) {
-            event.stopPropagation();
            this.copyLinkTypeToClipboard(type);
-            // As we prevented bubbling, the dropdown won't close by itself. We need to trigger it manually
-            this.share.dropdown('hide');
+            event.stopPropagation();
+            // As we prevented bubbling, the dropdown won't close by itself.
+            BootstrapUtils.hideDropdown(this.share);
        }
+        return false;
    }

    private getLinkOfType(type: LinkType): Promise<string> {
@@ -278,7 +293,7 @@ export class Sharing {
        return new Promise<string>((resolve, reject) => {
            Sharing.getLinks(config, type, (error: any, newUrl: string, extra: string, updateState: boolean) => {
                if (error || !newUrl) {
-                    this.displayTooltip(this.share, 'Oops, something went wrong');
+                    this.displayTooltip(this.shareTooltipTarget, 'Oops, something went wrong');
                    SentryCapture(error, 'Getting short link failed');
                    reject();
                } else {
@@ -295,7 +310,7 @@ export class Sharing {
        const config = this.layout.toConfig();
        Sharing.getLinks(config, type, (error: any, newUrl: string, extra: string, updateState: boolean) => {
            if (error || !newUrl) {
-                this.displayTooltip(this.share, 'Oops, something went wrong');
+                this.displayTooltip(this.shareTooltipTarget, 'Oops, something went wrong');
                SentryCapture(error, 'Getting short link failed');
            } else {
                if (updateState) {
@@ -306,16 +321,33 @@ export class Sharing {
        });
    }

+    // TODO we can consider using bootstrap's "Toast" support in future.
    private displayTooltip(where: JQuery, message: string): void {
-        where.tooltip('dispose');
-        where.tooltip({
-            placement: 'bottom',
-            trigger: 'manual',
-            title: message,
-        });
-        where.tooltip('show');
-        // Manual triggering of tooltips does not hide them automatically. This timeout ensures they do
-        setTimeout(() => where.tooltip('hide'), 1500);
+        // First dispose any existing tooltip
+        const tooltipEl = where[0];
+        if (!tooltipEl) return;
+
+        const existingTooltip = Tooltip.getInstance(tooltipEl);
+        if (existingTooltip) {
+            existingTooltip.dispose();
+        }
+
+        // Create and show new tooltip
+        try {
+            const tooltip = BootstrapUtils.initTooltip(tooltipEl, {
+                placement: 'bottom',
+                trigger: 'manual',
+                title: message,
+            });
+
+            tooltip.show();
+
+            // Manual triggering of tooltips does not hide them automatically. This timeout ensures they do
+            setTimeout(() => tooltip.hide(), 1500);
+        } catch (e) {
+            // If element doesn't exist, just silently fail
+            console.warn('Could not show tooltip:', e);
+        }
    }

    private openShareModalForType(type: LinkType): void {
@@ -336,7 +368,7 @@ export class Sharing {
        if (Sharing.isNavigatorClipboardAvailable()) {
            navigator.clipboard
                .writeText(link)
-                .then(() => this.displayTooltip(this.share, 'Link copied to clipboard'))
+                .then(() => this.displayTooltip(this.shareTooltipTarget, 'Link copied to clipboard'))
                .catch(() => this.openShareModalForType(type));
        } else {
            this.openShareModalForType(type);
@@ -397,7 +429,7 @@ export class Sharing {
    ): string {
        const embedUrl = Sharing.getEmbeddedUrl(config, root, isReadOnly, extraOptions);
        // The attributes must be double quoted, the full url's rison contains single quotes
-        return `<iframe width="800px" height="200px" src="${embedUrl}"></iframe>`;
+        return `<iframe width='800px' height='200px' src='${embedUrl}'></iframe>`;
    }

    private static getEmbeddedUrl(config: any, root: string, readOnly: boolean, extraOptions: object): string {
@@ -455,7 +487,7 @@ export class Sharing {
            const newElement = baseTemplate.children('a.share-item').clone();
            if (service.logoClass) {
                newElement.prepend(
-                    $('<span>').addClass('dropdown-icon mr-1').addClass(service.logoClass).prop('title', serviceName),
+                    $('<span>').addClass('dropdown-icon me-1').addClass(service.logoClass).prop('title', serviceName),
                );
            }
            if (service.text) {
--- a/static/styles/explorer.scss
+++ b/static/styles/explorer.scss
@@ -36,6 +36,11 @@ body {
    padding: 0;
 }

+// Fix for Bootstrap 5 navbar
+.navbar .container-fluid {
+    padding-left: 0;
+}
+
 .navbar-brand img.logo-overlay {
    position: absolute;
    top: 0;
@@ -75,13 +80,23 @@ body {

 .compiler-picker {
    min-width: 14em;
+    flex-grow: 0.2 !important; // Ensures the compiler picker doesn't flex-grow too much and take up more space
+}
+
+// Prevent TomSelect items from spilling onto multiple lines
+.ts-wrapper .item {
+    white-space: nowrap;
+    overflow: hidden;
 }

 .compiler-picker .ts-input {
    text-align: center;
-    border-left: none !important;
-    border-top-left-radius: 0;
-    border-bottom-left-radius: 0;
+    border-left: none !important; /* Fallback for older browsers */
+    border-inline-start: none !important; /* Logical property for RTL support */
+    border-top-left-radius: 0; /* Fallback for older browsers */
+    border-bottom-left-radius: 0; /* Fallback for older browsers */
+    border-start-start-radius: 0; /* Logical property for RTL support */
+    border-end-start-radius: 0; /* Logical property for RTL support */
 }

 .function-picker {
@@ -294,6 +309,12 @@ pre.content.wrap * {
    }
 }

+#site-template-loader {
+    .modal-dialog {
+        min-width: 800px; /* ensure template modal has adequate width */
+    }
+}
+
 .modal-body {
    min-height: 200px;
    overflow-y: auto; /* make body scrollable -> keep Header & Footer onscreen, if possible */
@@ -377,7 +398,7 @@ pre.content.wrap * {
    max-width: 100% !important;
 }

-.toast-header .close {
+.toast-header .btn-close {
    float: left;
    margin-right: 5px;
 }
@@ -387,17 +408,25 @@ pre.content.wrap * {
 }

 .font-size-list {
-    min-width: 43px !important;
-    max-height: 70% !important;
-    overflow-y: scroll;
+    min-width: 60px !important;
+    max-height: 70vh !important;
+    overflow-y: auto;
    width: auto;
    // For my fellow Firefox users
    scrollbar-width: thin;
+    padding: 0.25rem 0;
 }

 .font-size-list button {
    margin-left: 0 !important;
    border-radius: 0;
+    width: 100%;
+    text-align: center;
+    padding: 0.25rem 0.5rem;
+}
+
+.font-size-list button:hover {
+    background-color: rgba(0, 0, 0, 0.075);
 }

 .font-option {
@@ -893,17 +922,18 @@ div.populararguments div.dropdown-menu {
 }

 .corporate .ces {
-    font-size: 165%;
-    height: 9em;
+    .btn {
+        --bs-btn-font-size: 24px;
+    }
+    height: 20em;
 }

 .legendary .ces {
-    font-size: 165%;
-    height: 7em;
-}
-
-.legendary .ces button {
-    padding: 1em;
+    .btn {
+        --bs-btn-font-size: 24px;
+        padding: 1em;
+    }
+    height: 20em;
 }

 .ces-logo {
@@ -1115,7 +1145,7 @@ div.populararguments div.dropdown-menu {
    margin-right: 2pt;
 }

-span.badge.badge-pill {
+span.badge.rounded-pill {
    margin-left: 2pt;
 }

@@ -1185,11 +1215,42 @@ html[data-theme='one-dark'] {
    padding-right: 2rem !important;
 }

+/* Add back the dropdown arrow for TomSelect in Bootstrap 5 */
+.ts-wrapper.single .ts-control:not(.input-active)::after {
+    content: " ";
+    display: block;
+    position: absolute;
+    top: 50%;
+    right: 15px;
+    margin-top: -3px;
+    width: 0;
+    height: 0;
+    border-style: solid;
+    border-width: 5px 5px 0 5px;
+    border-color: #343a40 transparent transparent transparent;
+}
+
+/* Styling for the dropdown arrow when dropdown is active */
+.ts-wrapper.single.dropdown-active .ts-control::after {
+    margin-top: -4px;
+    border-width: 0 5px 5px 5px;
+    border-color: transparent transparent #343a40 transparent;
+}
+
+// Fix Bootstrap 5's input-group border overlap issues with TomSelect
+// Bootstrap applies a -1px margin to elements matching `:not(:first-child)` in input groups
+// TomSelect creates a wrapper (.ts-wrapper) around the select element, which becomes a
+// child of the input-group. This wrapper gets the negative margin, causing it to shift
+// left by 1px and visually overflow its container boundary.
+.input-group > .ts-wrapper:not(:first-child) {
+  margin-left: 0 !important; // Reset Bootstrap's negative margin for TomSelect wrappers
+}
+
 .copy-link-btn {
    padding-top: 0;
 }

-.conformance-wrapper .compiler-list .form-row {
+.conformance-wrapper .compiler-list .row {
    padding-top: 3px;
 }

@@ -1229,8 +1290,10 @@ html[data-theme='one-dark'] {

 .prepend-options,
 .picker-popout-button {
-    border-top-right-radius: 0;
-    border-bottom-right-radius: 0;
+    border-top-right-radius: 0; /* Fallback for older browsers */
+    border-bottom-right-radius: 0; /* Fallback for older browsers */
+    border-start-end-radius: 0; /* Logical property for RTL support */
+    border-end-end-radius: 0; /* Logical property for RTL support */
 }

 .picker-popout-button {
@@ -1257,7 +1320,9 @@ html[data-theme='one-dark'] {
 }

 .popular-arguments-btn {
-    border-top-right-radius: 0;
+    border-top-right-radius: 0; /* Fallback for older browsers */
+    border-start-end-radius: 0; /* Logical property for RTL support */
+    height: 100%;
 }

 .panel-compilation {
@@ -1315,9 +1380,14 @@ html[data-theme='one-dark'] {
    > div {
        padding: 0;
        flex-shrink: 0;
+        &.site-templates-list-col {
+            min-width: 150px;
+            width: 20%;
+        }
        &.site-template-preview-col {
            flex-grow: 1;
            flex-shrink: 1;
+            min-width: 400px;
            img {
                width: 1000px;
                aspect-ratio: 1000 / 800;
@@ -1579,11 +1649,11 @@ html[data-theme='one-dark'] {
            }
        }

-        .close {
+        .dark-close {
            position: absolute;
-            bottom: 0px;
+            bottom: 0;
            right: -12px;
-            //background: #e787e7;
+            padding: 0;
            background: linear-gradient(90deg, rgba(255, 255, 255, 0) 0%, #1a1a1a 48%, #1a1a1a 100%);
            width: 24px;
            height: 24px;
--- a/static/styles/themes/dark-theme.scss
+++ b/static/styles/themes/dark-theme.scss
@@ -28,12 +28,24 @@ body {
    background-color: #333 !important;
 }

+// Border color adjustments for form elements in dark theme
+.form-select,
+.form-control,
+.input-group-text,
+.ts-wrapper .ts-control {
+    --bs-border-color: #444;
+}
+
 input,
 textarea {
    color: #eee !important;
    background-color: #474747;
    border: 0 !important;

+    &::placeholder {
+        color: #888 !important;
+    }
+
    &:focus {
        color: #eee !important;
        background-color: #474747;
@@ -166,7 +178,7 @@ textarea.form-control {
 .conformance-wrapper {
    background-color: #1e1e1e !important;

-    .compiler-list .form-row {
+    .compiler-list .row {
        border-bottom: 1px solid #3e3e3e;
    }
 }
@@ -184,7 +196,7 @@ textarea.form-control {
    background-color: rgba(49, 54, 60, 0.85);
 }

-.custom-select {
+.form-select {
    background-color: #76a1c8 !important;
 }

@@ -196,6 +208,11 @@ textarea.form-control {
        color: #fff !important;
        background-color: #23272b !important;
    }
+
+    &.active {
+        background-color: #235765 !important;
+        color: #fff !important;
+    }
 }

 .dropdown-menu {
@@ -366,8 +383,8 @@ textarea.form-control {
    color: #eee !important;
    background-color: #333 !important;

-    .close {
-        color: #fff;
+    .btn-close {
+        filter: invert(100%);
    }
 }

@@ -437,8 +454,8 @@ textarea.form-control {
    background-color: #aa3333 !important;
    color: #fff;

-    .close {
-        color: #fff;
+    .btn-close {
+        filter: invert(100%);
    }
 }

@@ -451,8 +468,8 @@ textarea.form-control {
    background-color: #222 !important;
    color: #fff;

-    .close {
-        color: #fff;
+    .btn-close {
+        filter: invert(100%);
    }
 }

--- a/static/styles/themes/default-theme.scss
+++ b/static/styles/themes/default-theme.scss
@@ -164,16 +164,16 @@ a.navbar-brand img.logo.normal {
 .notification-error {
    background-color: indianred;
    color: white;
-    .close {
-        color: white;
+    .btn-close {
+        filter: invert(100%);
    }
 }

 .notification-on {
    background-color: green;
    color: #fff;
-    .close {
-        color: white;
+    .btn-close {
+        filter: invert(100%);
    }
 }

@@ -346,7 +346,7 @@ div.argmenuitem span.argdescription {
    color: #007bfd;
 }

-.conformance-wrapper .compiler-list .form-row {
+.conformance-wrapper .compiler-list .row {
    border-bottom: 1px solid #e3e3e3;
 }

@@ -387,6 +387,11 @@ div.argmenuitem span.argdescription {
    background-color: #dae0e5;
 }

+.dropdown-item.active {
+    background-color: #007bfd;
+    color: white;
+}
+
 .currentCursorPosition {
    color: #15a3b9;
    background-color: darken(rgba(248, 249, 250, 0.85), 3%);
--- a/static/styles/themes/one-dark-theme.scss
+++ b/static/styles/themes/one-dark-theme.scss
@@ -39,11 +39,23 @@ body {
    background-color: $base !important;
 }

+// Border color adjustments for form elements in dark theme
+.form-select,
+.form-control,
+.input-group-text,
+.ts-wrapper .ts-control {
+    --bs-border-color: $dark;
+}
+
 input {
    color: #eee !important;
    background-color: $lighter;
    border: 0 !important;

+    &::placeholder {
+        color: #888 !important;
+    }
+
    &:focus {
        color: #eee !important;
        background-color: $lightest;
@@ -204,7 +216,7 @@ textarea.form-control {
 .conformance-wrapper {
    background-color: #1e1e1e !important;

-    .compiler-list .form-row {
+    .compiler-list .row {
        border-bottom: 1px solid #3e3e3e;
    }
 }
@@ -222,7 +234,7 @@ textarea.form-control {
    background-color: opacify($dark, 0.8);
 }

-.custom-select {
+.form-select {
    background-color: #dddddd !important;
    color: #000 !important;
 }
@@ -235,6 +247,11 @@ textarea.form-control {
        color: #fff !important;
        background-color: $lighter !important;
    }
+
+    &.active {
+        background-color: #405f9d !important;
+        color: #fff !important;
+    }
 }

 .dropdown-menu {
@@ -325,7 +342,7 @@ textarea.form-control {
    }
 }

-#v-status {
+.v-status {
    color: #eee !important;
 }

@@ -422,8 +439,8 @@ textarea.form-control {
    color: #eee !important;
    background-color: $base !important;

-    .close {
-        color: #eee;
+    .btn-close {
+        filter: invert(90%);
    }
 }

@@ -493,8 +510,8 @@ textarea.form-control {
    background-color: #aa3333 !important;
    color: #fff;

-    .close {
-        color: #fff;
+    .btn-close {
+        filter: invert(100%);
    }
 }

@@ -507,8 +524,8 @@ textarea.form-control {
    background-color: #222 !important;
    color: #fff;

-    .close {
-        color: #fff;
+    .btn-close {
+        filter: invert(100%);
    }
 }

--- a/static/styles/themes/pink-theme.scss
+++ b/static/styles/themes/pink-theme.scss
@@ -36,6 +36,14 @@ body {
    background-color: $base !important;
 }

+// Border color adjustments for form elements
+.form-select,
+.form-control,
+.input-group-text,
+.ts-wrapper .ts-control {
+    --bs-border-color: $dark;
+}
+
 input {
    //color: #000 !important;
    background-color: $base;
@@ -174,7 +182,7 @@ textarea.form-control {
 .conformance-wrapper {
    background-color: #1e1e1e !important;

-    .compiler-list .form-row {
+    .compiler-list .row {
        border-bottom: 1px solid #3e3e3e;
    }
 }
@@ -188,7 +196,7 @@ textarea.form-control {
    background-color: opacify($dark, 0.8);
 }

-.custom-select {
+.form-select {
    background-color: #76a1c8 !important;
 }

@@ -198,6 +206,11 @@ textarea.form-control {
    &:hover {
        background-color: $dark !important;
    }
+
+    &.active {
+        background-color: $darker !important;
+        color: #212529 !important;
+    }
 }

 .dropdown-menu {
@@ -383,10 +396,6 @@ textarea.form-control {
    color: #212529 !important;
    background-color: $base !important;
    border-bottom-color: $dark;
-
-    .close {
-        color: #212529;
-    }
 }

 .nav.nav-tabs {
@@ -459,8 +468,8 @@ textarea.form-control {
    background-color: #aa3333 !important;
    color: #fff;

-    .close {
-        color: #fff;
+    .btn-close {
+        filter: invert(100%);
    }
 }

@@ -473,8 +482,8 @@ textarea.form-control {
    background-color: #222 !important;
    color: #fff;

-    .close {
-        color: #fff;
+    .btn-close {
+        filter: invert(100%);
    }
 }

--- a/static/widgets/alert.ts
+++ b/static/widgets/alert.ts
@@ -24,6 +24,7 @@

 import $ from 'jquery';

+import * as BootstrapUtils from '../bootstrap-utils.js';
 import {AlertAskOptions, AlertEnterTextOptions, AlertNotifyOptions} from './alert.interfaces.js';

 export class Alert {
@@ -57,10 +58,10 @@ export class Alert {
        modal.toggleClass('error-alert', isError === true);
        modal.find('.modal-title').html(title);
        modal.find('.modal-body').html(body);
-        modal.modal();
+        BootstrapUtils.showModal(modal);
+
        if (onClose) {
-            modal.off('hidden.bs.modal');
-            modal.on('hidden.bs.modal', onClose);
+            BootstrapUtils.setElementEventHandler(modal, 'hidden.bs.modal', onClose);
        }
        return modal;
    }
@@ -83,10 +84,10 @@ export class Alert {
            modal.find('.modal-footer .no').removeClass('btn-link').addClass(askOptions.noClass);
        }
        if (askOptions.onClose) {
-            modal.off('hidden.bs.modal');
-            modal.on('hidden.bs.modal', askOptions.onClose);
+            BootstrapUtils.setElementEventHandler(modal, 'hidden.bs.modal', askOptions.onClose);
        }
-        modal.modal();
+
+        BootstrapUtils.showModal(modal);
        return modal;
    }

@@ -108,10 +109,8 @@ export class Alert {
        const newElement = $(`
            <div class="toast" tabindex="-1" role="alert" aria-live="assertive" aria-atomic="true">
                <div class="toast-header ${alertClass}">
-                    <strong class="mr-auto">${this.prefixMessage}</strong>
-                    <button type="button" class="ml-2 mb-1 close" data-dismiss="toast" aria-label="Close">
-                        <span aria-hidden="true">&times;</span>
-                    </button>
+                    <strong class="me-auto">${this.prefixMessage}</strong>
+                    <button type="button" class="ms-2 mb-1 btn-close" data-bs-dismiss="toast" aria-label="Close"></button>
                </div>
                <div class="toast-body ${alertClass}">
                    <span id="msg">${body}</span>
@@ -119,21 +118,26 @@ export class Alert {
            </div>
        `);
        container.append(newElement);
-        newElement.toast({
+        const toastOptions = {
            autohide: autoDismiss,
            delay: dismissTime,
-        });
+        };
+
+        BootstrapUtils.initToast(newElement, toastOptions);
+
        if (group !== '') {
            if (collapseSimilar) {
                // Only collapsing if a group has been specified
                const old = container.find(`[data-group="${group}"]`);
-                old.toast('hide');
-                old.remove();
+                old.each((_, element) => {
+                    BootstrapUtils.hideToast(element);
+                    $(element).remove();
+                });
            }
            newElement.attr('data-group', group);
        }
        onBeforeShow(newElement);
-        newElement.toast('show');
+        BootstrapUtils.showToast(newElement);
    }

    /**
@@ -174,14 +178,13 @@ export class Alert {
            noButton.removeClass('btn-light').addClass(askOptions.noClass);
        }
        if (askOptions.onClose) {
-            modal.off('hidden.bs.modal');
-            modal.on('hidden.bs.modal', askOptions.onClose);
+            BootstrapUtils.setElementEventHandler(modal, 'hidden.bs.modal', askOptions.onClose);
        }

-        modal.on('shown.bs.modal', () => {
+        BootstrapUtils.setElementEventHandler(modal, 'shown.bs.modal', () => {
            answerEdit.trigger('focus');
        });
-        modal.modal();
+        BootstrapUtils.showModal(modal);
        return modal;
    }
 }
--- a/static/widgets/compiler-overrides.ts
+++ b/static/widgets/compiler-overrides.ts
@@ -30,6 +30,7 @@ import {
    EnvVarOverrides,
 } from '../../types/compilation/compiler-overrides.interfaces.js';
 import {assert, unwrap} from '../assert.js';
+import * as BootstrapUtils from '../bootstrap-utils.js';
 import {CompilerInfo} from '../compiler.interfaces.js';
 import {localStorage} from '../local.js';
 import {options} from '../options.js';
@@ -160,8 +161,8 @@ export class CompilerOverridesWidget {
            btn.addClass('active');
        } else if (state instanceof IncompatibleState) {
            btn.prop('disabled', true);
-            btn.prop('data-toggle', 'tooltip');
-            btn.prop('data-placement', 'top');
+            btn.prop('data-bs-toggle', 'tooltip');
+            btn.prop('data-bs-placement', 'top');
            btn.prop('title', state.reason);
        }
        div.data('ov-name', fave.name);
@@ -416,9 +417,8 @@ export class CompilerOverridesWidget {

        const lastOverrides = JSON.stringify(this.configured);

-        const popup = this.popupDomRoot.modal();
        // popup is shared, so clear the events first
-        popup.off('hidden.bs.modal').on('hidden.bs.modal', () => {
+        BootstrapUtils.setElementEventHandler(this.popupDomRoot, 'hidden.bs.modal', () => {
            this.configured = this.loadStateFromUI();

            const newOverrides = JSON.stringify(this.configured);
@@ -428,5 +428,7 @@ export class CompilerOverridesWidget {
                this.onChangeCallback();
            }
        });
+
+        BootstrapUtils.showModal(this.popupDomRoot);
    }
 }
--- a/static/widgets/compiler-picker-popup.ts
+++ b/static/widgets/compiler-picker-popup.ts
@@ -29,6 +29,7 @@ import * as sifter from '@orchidjs/sifter';
 import {escapeHTML, intersection, remove, unique} from '../../shared/common-utils.js';
 import {CompilerInfo} from '../../types/compiler.interfaces.js';
 import {unwrap, unwrapString} from '../assert.js';
+import * as BootstrapUtils from '../bootstrap-utils.js';
 import {CompilerService} from '../compiler-service.js';
 import {highlight} from '../highlight.js';
 import {CompilerPicker} from './compiler-picker.js';
@@ -64,7 +65,7 @@ export class CompilerPickerPopup {
        this.categoryFilters = [];
        this.searchBar.val('');

-        this.modal.on('shown.bs.modal', () => {
+        BootstrapUtils.setElementEventHandler(this.modal, 'shown.bs.modal', () => {
            this.searchBar[0].focus();
        });
    }
@@ -186,7 +187,7 @@ export class CompilerPickerPopup {
                    `
                    <div class="compiler d-flex" data-value="${compiler.id}">
                        <div>${searchRegexes ? highlight(name, searchRegexes) : name}</div>
-                        <div title="Click to mark or unmark as a favorite" class="ml-auto toggle-fav">
+                        <div title="Click to mark or unmark as a favorite" class="ms-auto toggle-fav">
                            <i class="${extraClasses}"></i>
                        </div>
                    </div>
@@ -264,10 +265,10 @@ export class CompilerPickerPopup {
    show() {
        this.searchBar.trigger('input');
        this.fillCompilers();
-        this.modal.modal({});
+        BootstrapUtils.showModal(this.modal);
    }

    hide() {
-        this.modal.modal('hide');
+        BootstrapUtils.hideModal(this.modal);
    }
 }
--- a/static/widgets/compiler-picker.ts
+++ b/static/widgets/compiler-picker.ts
@@ -135,7 +135,7 @@ export class CompilerPicker {
                        '<div class="d-flex"><div>' +
                        escapeHtml(data.name) +
                        '</div>' +
-                        '<div title="Click to mark or unmark as a favorite" class="ml-auto toggle-fav">' +
+                        '<div title="Click to mark or unmark as a favorite" class="ms-auto toggle-fav">' +
                        '<i class="' +
                        extraClasses +
                        '"></i>' +
@@ -143,6 +143,7 @@ export class CompilerPicker {
                        '</div>'
                    );
                },
+                item: (data, escapeHtml) => `<div title="${escapeHtml(data.name)}">${escapeHtml(data.name)}</div>`,
            },
        });

--- a/static/widgets/compiler-version-info.ts
+++ b/static/widgets/compiler-version-info.ts
@@ -24,6 +24,7 @@

 import $ from 'jquery';
 import {escapeHTML} from '../../shared/common-utils.js';
+import * as BootstrapUtils from '../bootstrap-utils.js';
 import {options} from '../options.js';

 export type CompilerVersionInfo = {version: string; fullVersion?: string};
@@ -78,14 +79,19 @@ function reallySetCompilerVersionPopover(
            .on('click', () => {
                versionContent.toggle();
                hiddenVersionText.toggle();
-                pane.fullCompilerName.popover('update');
+                const popover = BootstrapUtils.getPopoverInstance(pane.fullCompilerName);
+                if (popover) popover.update();
            });
        hiddenSection.append(hiddenVersionText).append(clickToExpandContent);
        bodyContent.append(hiddenSection);
    }

-    pane.fullCompilerName.popover('dispose');
-    pane.fullCompilerName.popover({
+    // Dispose of existing popover
+    const existingPopover = BootstrapUtils.getPopoverInstance(pane.fullCompilerName);
+    if (existingPopover) existingPopover.dispose();
+
+    // Initialize new popover
+    BootstrapUtils.initPopover(pane.fullCompilerName, {
        html: true,
        title: notification
            ? ($.parseHTML('<span>Compiler Version: ' + notification + '</span>')[0] as Element)
--- a/static/widgets/fontscale.ts
+++ b/static/widgets/fontscale.ts
@@ -47,11 +47,7 @@ function makeFontSizeDropdown(elem: JQuery, obj: FontScale, buttonDropdown: JQue
    for (let i = 8; i <= 30; i++) {
        const item = $('<button></button>');

-        item.attr('data-value', i)
-            .addClass('dropdown-item btn btn-sm btn-light')
-            .text(i)
-            .appendTo(elem)
-            .on('click', onClickEvent);
+        item.attr('data-value', i).addClass('dropdown-item').text(i).appendTo(elem).on('click', onClickEvent);

        if (obj.scale === i) {
            item.addClass('active');
--- a/static/widgets/history-widget.ts
+++ b/static/widgets/history-widget.ts
@@ -25,9 +25,10 @@
 import $ from 'jquery';
 import {editor} from 'monaco-editor';
 import {pluck} from 'underscore';
+import {unwrap} from '../assert.js';
+import * as BootstrapUtils from '../bootstrap-utils.js';
 import {EditorSource, HistoryEntry, sortedList} from '../history.js';
 import ITextModel = editor.ITextModel;
-import {unwrap} from '../assert.js';

 type Entry = {dt: number; name: string; load: () => void};

@@ -72,7 +73,9 @@ export class HistoryWidget {
                    name: `${dt.replace(/\s\(.*\)/, '')} (${languages})`,
                    load: () => {
                        this.onLoad(data);
-                        this.modal?.modal('hide');
+                        if (this.modal) {
+                            BootstrapUtils.hideModal(this.modal);
+                        }
                    },
                };
            }),
@@ -140,7 +143,8 @@ export class HistoryWidget {
        this.onLoadCallback = onLoad;

        // It can't tell that we initialize modal on initializeIfNeeded, so it sticks to the possibility of it being null
-        unwrap(this.modal).on('shown.bs.modal', () => this.resizeLayout());
-        unwrap(this.modal).modal();
+        const modalElement = unwrap(this.modal)[0];
+        modalElement.addEventListener('shown.bs.modal', () => this.resizeLayout());
+        BootstrapUtils.showModal(modalElement);
    }
 }
--- a/static/widgets/libs-widget.ts
+++ b/static/widgets/libs-widget.ts
@@ -24,6 +24,7 @@

 import $ from 'jquery';
 import {unwrapString} from '../assert.js';
+import * as BootstrapUtils from '../bootstrap-utils.js';
 import {localStorage} from '../local.js';
 import {Library, LibraryVersion} from '../options.interfaces.js';
 import {options} from '../options.js';
@@ -187,32 +188,32 @@ export class LibsWidget {
            this.domRoot.addClass('mobile');
        }

-        this.domRoot
-            .on('shown.bs.modal', () => {
-                searchInput.trigger('focus');
+        BootstrapUtils.setElementEventHandler(this.domRoot, 'shown.bs.modal', () => {
+            searchInput.trigger('focus');

-                for (const filter of this.filters) {
-                    const filterResult = filter(this.currentCompilerId, this.currentLangId);
-                    if (filterResult !== null) {
-                        const alertSystem = new Alert();
-                        alertSystem.notify(`${filterResult.title}: ${filterResult.content}`, {
-                            group: 'libs',
-                            alertClass: 'notification-error',
-                        });
-                        break;
-                    }
+            for (const filter of this.filters) {
+                const filterResult = filter(this.currentCompilerId, this.currentLangId);
+                if (filterResult !== null) {
+                    const alertSystem = new Alert();
+                    alertSystem.notify(`${filterResult.title}: ${filterResult.content}`, {
+                        group: 'libs',
+                        alertClass: 'notification-error',
+                    });
+                    break;
                }
-            })
-            .on('hide.bs.modal', () => {
-                this.hidePopups();
-            });
+            }
+        });
+
+        BootstrapUtils.setElementEventHandler(this.domRoot, 'hide.bs.modal', () => {
+            this.hidePopups();
+        });

        searchInput.on('input', this.startSearching.bind(this));

        this.domRoot.find('.lib-search-button').on('click', this.startSearching.bind(this));

        this.dropdownButton.on('click', () => {
-            this.domRoot.modal({});
+            BootstrapUtils.showModal(this.domRoot);
        });

        this.updateButton();
@@ -342,11 +343,14 @@ export class LibsWidget {
    }

    hidePopups() {
-        this.searchResults.find('.lib-info-button').popover('hide');
+        this.searchResults.find('.lib-info-button').each((_, el) => BootstrapUtils.hidePopover($(el)));
    }

    clearSearchResults() {
-        this.searchResults.find('.lib-info-button').popover('dispose');
+        this.searchResults.find('.lib-info-button').each((_, el) => {
+            const popover = BootstrapUtils.getPopoverInstance($(el));
+            if (popover) popover.dispose();
+        });
        this.searchResults.html('');
    }

@@ -498,7 +502,7 @@ export class LibsWidget {
            '<div class="arrow"></div>' +
            '<h3 class="popover-header"></h3><div class="popover-body"></div>' +
            '</div>';
-        infoButton.popover({
+        BootstrapUtils.initPopover(infoButton, {
            html: true,
            title: 'Build info for ' + getCompilerName(this.currentCompilerId),
            content: () => {
--- a/static/widgets/load-save.ts
+++ b/static/widgets/load-save.ts
@@ -29,6 +29,7 @@ import {escapeHTML} from '../../shared/common-utils.js';
 import {Language} from '../../types/languages.interfaces.js';
 import {SourceApiEntry} from '../../types/source.interfaces.js';
 import {unwrap, unwrapString} from '../assert.js';
+import * as BootstrapUtils from '../bootstrap-utils.js';
 import {HistorySource} from '../history.js';
 import {localStorage} from '../local.js';
 import {Alert} from './alert.js';
@@ -98,7 +99,9 @@ export class LoadSave {
            window.location.origin + this.base + 'source/builtin/load/' + element.lang + '/' + element.file,
            response => this.onLoad(response.file),
        );
-        this.modal?.modal('hide');
+        if (this.modal) {
+            BootstrapUtils.hideModal(this.modal);
+        }
    }

    private static populate(root: JQuery, list: PopulateItem[]) {
@@ -143,7 +146,9 @@ export class LoadSave {
                    name: name,
                    load: () => {
                        this.onLoad(data);
-                        this.modal?.modal('hide');
+                        if (this.modal) {
+                            BootstrapUtils.hideModal(this.modal);
+                        }
                    },
                    delete: () => {
                        this.alertSystem.ask(
@@ -183,7 +188,9 @@ export class LoadSave {
                    name: dt.replace(/\s\(.*\)/, ''),
                    load: () => {
                        this.onLoad(data.source);
-                        this.modal?.modal('hide');
+                        if (this.modal) {
+                            BootstrapUtils.hideModal(this.modal);
+                        }
                    },
                };
            }),
@@ -214,7 +221,9 @@ export class LoadSave {
            };
            reader.readAsText(file);
        }
-        this.modal?.modal('hide');
+        if (this.modal) {
+            BootstrapUtils.hideModal(this.modal);
+        }
    }

    public run(onLoad, editorText, currentLanguage: Language) {
@@ -224,7 +233,11 @@ export class LoadSave {
        this.populateLocalHistory();
        this.onLoadCallback = onLoad;
        unwrap(this.modal).find('.local-file').attr('accept', currentLanguage.extensions.join(','));
-        this.populateBuiltins().then(() => this.modal?.modal());
+        this.populateBuiltins().then(() => {
+            if (this.modal) {
+                BootstrapUtils.showModal(this.modal);
+            }
+        });
    }

    private onSaveToBrowserStorage() {
@@ -238,7 +251,9 @@ export class LoadSave {
            LoadSave.setLocalFile(name, this.editorText);
        };
        if (name in LoadSave.getLocalFiles()) {
-            this.modal?.modal('hide');
+            if (this.modal) {
+                BootstrapUtils.hideModal(this.modal);
+            }
            this.alertSystem.ask(
                'Replace current?',
                `Do you want to replace the existing saved file '${escapeHTML(name)}'?`,
@@ -246,7 +261,9 @@ export class LoadSave {
            );
        } else {
            doneCallback();
-            this.modal?.modal('hide');
+            if (this.modal) {
+                BootstrapUtils.hideModal(this.modal);
+            }
        }
    }

--- a/static/widgets/runtime-tools.ts
+++ b/static/widgets/runtime-tools.ts
@@ -32,6 +32,7 @@ import {
    RuntimeToolType,
 } from '../../types/execution/execution.interfaces.js';
 import {assert} from '../assert.js';
+import * as BootstrapUtils from '../bootstrap-utils.js';
 import {CompilerInfo} from '../compiler.interfaces.js';
 import {localStorage} from '../local.js';
 import {options} from '../options.js';
@@ -392,9 +393,8 @@ export class RuntimeToolsWidget {

        const lastOverrides = JSON.stringify(this.configured);

-        const popup = this.popupDomRoot.modal();
        // popup is shared, so clear the events first
-        popup.off('hidden.bs.modal').on('hidden.bs.modal', () => {
+        BootstrapUtils.setElementEventHandler(this.popupDomRoot, 'hidden.bs.modal', () => {
            this.configured = this.loadStateFromUI();

            const newOverrides = JSON.stringify(this.configured);
@@ -404,5 +404,7 @@ export class RuntimeToolsWidget {
                this.onChangeCallback();
            }
        });
+
+        BootstrapUtils.showModal(this.popupDomRoot);
    }
 }
--- a/static/widgets/site-templates-widget.ts
+++ b/static/widgets/site-templates-widget.ts
@@ -28,6 +28,7 @@ import GoldenLayout from 'golden-layout';
 import {escapeHTML} from '../../shared/common-utils.js';
 import {SiteTemplateResponse, UserSiteTemplate} from '../../types/features/site-templates.interfaces.js';
 import {assert, unwrap, unwrapString} from '../assert.js';
+import * as BootstrapUtils from '../bootstrap-utils.js';
 import {localStorage} from '../local.js';
 import {Settings} from '../settings.js';
 import * as url from '../url.js';
@@ -174,7 +175,7 @@ class SiteTemplatesWidget {
        this.populated = true;
    }
    show() {
-        this.modal.modal('show');
+        BootstrapUtils.showModal(this.modal);
        if (!this.populated) {
            this.populate();
        }
--- a/static/widgets/timing-info-widget.ts
+++ b/static/widgets/timing-info-widget.ts
@@ -24,11 +24,12 @@

 import {Chart, ChartData, defaults} from 'chart.js';
 import $ from 'jquery';
-import {Settings} from '../settings.js';
-import 'chart.js/auto';
 import {isString} from '../../shared/common-utils.js';
 import {CompilationResult} from '../../types/compilation/compilation.interfaces.js';
 import {unwrap} from '../assert.js';
+import * as BootstrapUtils from '../bootstrap-utils.js';
+import {Settings} from '../settings.js';
+import 'chart.js/auto';

 type Data = ChartData<'bar', number[], string> & {steps: number};

@@ -188,7 +189,7 @@ function displayData(data: Data) {
            },
        },
    });
-    modal.modal('show');
+    BootstrapUtils.showModal(modal);
 }

 export function displayCompilationTiming(compileResult: CompilationResult | null, totalTime: number) {
--- a/views/bits/sponsors-content.pug
+++ b/views/bits/sponsors-content.pug
@@ -24,8 +24,8 @@ block content
          div.ces-item-description= level.description
          .ces-top
            each sponsor in level.sponsors
-              .ces
-                button.btn-block.btn-secondary(title=sponsor.title onclick=sponsor.onclick disabled=!sponsor.url style=sponsor.style)
+              .ces.d-grid
+                button.btn.btn-secondary(title=sponsor.title onclick=sponsor.onclick disabled=!sponsor.url style=sponsor.style)
                  if sponsor.displayType === 'SideBySide'
                    .d-flex
                      .ces-item-title
--- a/views/font-size.pug
+++ b/views/font-size.pug
@@ -1,4 +1,4 @@
 .btn-group.btn-group-sm(role="group" aria-label="Font size")
-  button.dropdown-toggle.btn.btn-light.fs-button(type="button" title="Change font size\nTip #1: You can use scroll wheel while hovering over this button\nTip #2: You can ctrl+click this button to reset to default" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" data-flip="false" data-boundary="viewport")
+  button.dropdown-toggle.btn.btn-light.fs-button(type="button" title="Change font size\nTip #1: You can use scroll wheel while hovering over this button\nTip #2: You can ctrl+click this button to reset to default" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false" data-bs-flip="false" data-bs-boundary="viewport")
    span.fa.fa-font #[b.caret]
  .dropdown-menu.font-size-list(aria-labelledby="fs-button")
--- a/views/index.pug
+++ b/views/index.pug
@@ -2,111 +2,116 @@ extends _layout.pug

 block prepend content
  nav.navbar.navbar-godbolt.navbar-expand-md.navbar-light.bg-light
-    include logo.pug
-    button.navbar-toggler(type="button" data-toggle="collapse" data-target="#navbarContent" aria-controls="navbarContent" aria-expanded="false" aria-label="Toggle navigation")
-      span.navbar-toggler-icon
-    .collapse.navbar-collapse#navbarContent
-      ul.navbar-nav.navbar-left.mr-auto
-        li.nav-item.dropdown
-          button.btn.btn-light.nav-link.dropdown-toggle#addDropdown(role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false") Add...
-          div.dropdown-menu(aria-labelledby="addDropdown")
-            button.dropdown-item.btn#add-editor(title="Click or drag to desired destination")
-              span.dropdown-icon.fa.fa-code
-              | Source Editor
-            button.dropdown-item.btn#add-diff(title="Click or drag to desired destination")
-              span.dropdown-icon.fas.fa-exchange-alt
-              | Diff View
-            button.dropdown-item.btn#add-tree(title="Click or drag to desired destination")
-              span.dropdown-icon.fa.fa-list-alt
-              | Tree (IDE Mode)
-        li.nav-item.dropdown
-          button.btn.btn-light.nav-link.dropdown-toggle#moreDropdown(role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" data-cy="more-dropdown-btn") More
-          div.dropdown-menu(aria-labelledby="moreDropdown")
-            button.dropdown-item.btn#setting(data-target="#settings" data-toggle="modal")
-              span.dropdown-icon.fas.fa-sliders-h
-              | Settings
-            div.dropdown-divider
-            a.dropdown-item.btn#ui-brokenlink
-              span.dropdown-icon.fas.fa-undo-alt
-              | Reset UI layout
-            button.dropdown-item.btn#ui-reset(data-cy="reset-ui-btn")
-              span.dropdown-icon.fas.fa-trash-alt
-              | Reset code and UI layout
-            button.dropdown-item.btn#ui-duplicate
-              span.dropdown-icon.fas.fa-external-link-alt
-              | Open new tab
-            button.dropdown-item.btn#ui-history
-              span.dropdown-icon.fas.fa-exchange-alt
-              | History
-            div.dropdown-divider
-            button.dropdown-item.btn#ui-apply-default-font-scale
-              span.dropdown-icon.fas.fa-font
-              | Apply Default Font Scale
-        li.nav-item
-            button.btn.btn-light.nav-link#loadSiteTemplate(role="button") Templates
-        li.nav-item.shortlinkInfo.d-none
-          button.btn.btn-light.nav-link.shortlinkInfoBtn
-            span.fa.fa-info-circle
-            span.hideable.shortlinkInfoText
-        li.nav-item.ui-presentation-control.d-none
-          a.nav-link.ui-presentation-first(href="javascript:;")
-            span.dropdown-icon.fas.fa-fast-backward
-            | Start
-        li.nav-item.ui-presentation-control.d-none
-          a.nav-link.ui-presentation-prev(href="javascript:;")
-            span.dropdown-icon.fas.fa-backward
-            | Previous
-        li.nav-item.ui-presentation-control.d-none
-          a.nav-link.ui-presentation-next(href="javascript:;")
-            span.dropdown-icon.fas.fa-forward
-            | Next
-      ul#motd.navbar-nav.navbar-left.mr-auto.community-advert.d-none
-        span.content
-          | Thanks for using Compiler Explorer
-        span.community-hide(title="Hide and never show again" aria-label="Close")
-          button.close(type="button" aria-hidden="true") &times;
-      ul.navbar-nav.navbar-right
-        if showSponsors
-          li.nav-item.btn.btn-outline-info#ces(data-toggle="modal")
-            span#ces-banner-text Sponsors
-            include sponsor-icons.pug
-        li.nav-item.dropdown
-          button.btn.btn-light.nav-link.dropdown-toggle#share(role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false") Share
-          div.dropdown-menu.dropdown-menu-right
-            if storageSolution !== "null"
-              a.dropdown-item#shareShort(href="javascript:;" data-target="#sharelinkdialog" data-toggle="modal" data-bind="Short")
-                span.dropdown-icon.fas.fa-cloud.d-inline
-                | Short Link
-                button.btn.btn-sm.copy-link-btn.clip-icon.float-right(data-toggle="none")
-                  span.dropdown-icon.fa.fa-clipboard
-            a.dropdown-item#shareFull(href="javascript:;" data-target="#sharelinkdialog" data-toggle="modal" data-bind="Full")
-              span.dropdown-icon.fas.fa-store-slash.d-inline
-              | Full Link
-              button.btn.btn-sm.copy-link-btn.clip-icon.float-right(data-toggle="none")
-                span.dropdown-icon.fa.fa-clipboard
-            a.dropdown-item#shareEmbed(href="javascript:;" data-target="#sharelinkdialog" data-toggle="modal" data-bind="Embed")
-              span.dropdown-icon.fas.fa-window-restore.d-inline
-              | Embed in iframe
-              // This is not an oversight, there is in fact a .float-right missing here that's there in the other 2
-              button.btn.btn-sm.copy-link-btn.clip-icon(data-toggle="none")
-                span.dropdown-icon.fa.fa-clipboard
-        if policies.cookies.enabled || policies.privacy.enabled
+    .container-fluid
+      include logo.pug
+      button.navbar-toggler(type="button" data-bs-toggle="collapse" data-bs-target="#navbarContent" aria-controls="navbarContent" aria-expanded="false" aria-label="Toggle navigation")
+        span.navbar-toggler-icon
+      .collapse.navbar-collapse#navbarContent
+        ul.navbar-nav.me-auto.mb-2.mb-md-0
          li.nav-item.dropdown
-            button.btn.btn-light.nav-link.dropdown-toggle#policiesDropdown(role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false")
-              | Policies
-              span#policyBellNotification.d-none.badge.badge-pill.badge-primary
-                span.fa.fa-bell
-            div.dropdown-menu.dropdown-menu-right(aria-labelledby="policiesDropdown")
-              include menu-policies.pug
-        li.nav-item.dropdown
-          button.btn.btn-light.nav-link.dropdown-toggle#otherDropdown(role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false") Other
-          div.dropdown-menu.dropdown-menu-right(aria-labelledby="otherDropdown")
-            include menu-other.pug
+            button.btn.btn-light.nav-link.dropdown-toggle#addDropdown(role="button" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false") Add...
+            div.dropdown-menu(aria-labelledby="addDropdown")
+              button.dropdown-item.btn#add-editor(title="Click or drag to desired destination")
+                span.dropdown-icon.fa.fa-code
+                | Source Editor
+              button.dropdown-item.btn#add-diff(title="Click or drag to desired destination")
+                span.dropdown-icon.fas.fa-exchange-alt
+                | Diff View
+              button.dropdown-item.btn#add-tree(title="Click or drag to desired destination")
+                span.dropdown-icon.fa.fa-list-alt
+                | Tree (IDE Mode)
+          li.nav-item.dropdown
+            button.btn.btn-light.nav-link.dropdown-toggle#moreDropdown(role="button" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false" data-cy="more-dropdown-btn") More
+            div.dropdown-menu(aria-labelledby="moreDropdown")
+              button.dropdown-item.btn#setting(data-bs-target="#settings" data-bs-toggle="modal")
+                span.dropdown-icon.fas.fa-sliders-h
+                | Settings
+              div.dropdown-divider
+              a.dropdown-item.btn#ui-brokenlink
+                span.dropdown-icon.fas.fa-undo-alt
+                | Reset UI layout
+              button.dropdown-item.btn#ui-reset(data-cy="reset-ui-btn")
+                span.dropdown-icon.fas.fa-trash-alt
+                | Reset code and UI layout
+              button.dropdown-item.btn#ui-duplicate
+                span.dropdown-icon.fas.fa-external-link-alt
+                | Open new tab
+              button.dropdown-item.btn#ui-history
+                span.dropdown-icon.fas.fa-exchange-alt
+                | History
+              div.dropdown-divider
+              button.dropdown-item.btn#ui-apply-default-font-scale
+                span.dropdown-icon.fas.fa-font
+                | Apply Default Font Scale
+          li.nav-item
+            button.btn.btn-light.nav-link#loadSiteTemplate(role="button") Templates
+          li.nav-item.shortlinkInfo.d-none
+            button.btn.btn-light.nav-link.shortlinkInfoBtn
+              span.fa.fa-info-circle
+              span.hideable.shortlinkInfoText
+          li.nav-item.ui-presentation-control.d-none
+            a.nav-link.ui-presentation-first(href="javascript:;")
+              span.dropdown-icon.fas.fa-fast-backward
+              | Start
+          li.nav-item.ui-presentation-control.d-none
+            a.nav-link.ui-presentation-prev(href="javascript:;")
+              span.dropdown-icon.fas.fa-backward
+              | Previous
+          li.nav-item.ui-presentation-control.d-none
+            a.nav-link.ui-presentation-next(href="javascript:;")
+              span.dropdown-icon.fas.fa-forward
+              | Next
+
+        ul#motd.navbar-nav.community-advert.d-none.mx-auto
+          span.content
+            | Thanks for using Compiler Explorer
+          span.community-hide(title="Hide and never show again" aria-label="Close")
+            button.btn-close(type="button" aria-label="Close")
+
+        ul.navbar-nav.ms-auto.mb-2.mb-md-0
+          if showSponsors
+            li.nav-item.btn.btn-outline-info#ces
+              span#ces-banner-text Sponsors
+              include sponsor-icons.pug
+          li.nav-item.dropdown#share-tooltip-target
+            button.btn.btn-light.nav-link.dropdown-toggle#share(role="button" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false") Share
+            div.dropdown-menu.dropdown-menu-end
+              // In order for these to support both the clipboard button _and_ optionally opening the dialog, we can't
+              // use `data-bs-toggle="modal"` on the `<a>` itself, as that would prevent the clipboard button from working.
+              // Bootstrap's default blanket event handler beats out any event handler we manually attach to the button.
+              if storageSolution !== "null"
+                a.dropdown-item#shareShort(href="javascript:;" data-bs-target="#sharelinkdialog" data-bind="Short")
+                  span.dropdown-icon.fas.fa-cloud.d-inline
+                  | Short Link
+                  button.btn.btn-sm.copy-link-btn.clip-icon.float-end(data-bs-target="" data-bs-toggle="none")
+                    span.dropdown-icon.fa.fa-clipboard
+              a.dropdown-item#shareFull(href="javascript:;" data-bs-target="#sharelinkdialog" data-bind="Full")
+                span.dropdown-icon.fas.fa-store-slash.d-inline
+                | Full Link
+                button.btn.btn-sm.copy-link-btn.clip-icon.float-end(data-bs-toggle="none")
+                  span.dropdown-icon.fa.fa-clipboard
+              a.dropdown-item#shareEmbed(href="javascript:;" data-bs-target="#sharelinkdialog" data-bind="Embed")
+                span.dropdown-icon.fas.fa-window-restore.d-inline
+                | Embed in iframe
+                // This is not an oversight, there is in fact a .float-end missing here that's there in the other 2
+                button.btn.btn-sm.copy-link-btn.clip-icon(data-bs-toggle="none")
+                  span.dropdown-icon.fa.fa-clipboard
+          if policies.cookies.enabled || policies.privacy.enabled
+            li.nav-item.dropdown
+              button.btn.btn-light.nav-link.dropdown-toggle#policiesDropdown(role="button" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false")
+                | Policies
+                span#policyBellNotification.d-none.badge.rounded-pill.bg-primary
+                  span.fa.fa-bell
+              div.dropdown-menu.dropdown-menu-end(aria-labelledby="policiesDropdown")
+                include menu-policies.pug
+          li.nav-item.dropdown
+            button.btn.btn-light.nav-link.dropdown-toggle#otherDropdown(role="button" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false") Other
+            div.dropdown-menu.dropdown-menu-end(aria-labelledby="otherDropdown")
+              include menu-other.pug

 block append footer
  include popups/_all
  #real-dark
  #true-dark
    .content Try the real dark theme 🔦
-      .close
-        i.fa-solid.fa-xmark
+      button.btn.dark-close.fas.fa-times(type="button" aria-label="Close")
--- a/views/menu-policies.pug
+++ b/views/menu-policies.pug
@@ -1,10 +1,10 @@
 button.dropdown-item.btn#cookies
  span.dropdown-icon.fas.fa-cookie-bite
  | Cookie policy
-  span#cookiesBellNotification.d-none.badge.badge-pill.badge-primary
+  span#cookiesBellNotification.d-none.badge.rounded-pill.bg-primary
    span.fa.fa-bell
 button.dropdown-item.btn#privacy
  span.dropdown-icon.fas.fa-user-lock
  | Privacy policy
-  span#privacyBellNotification.d-none.badge.badge-pill.badge-primary
+  span#privacyBellNotification.d-none.badge.rounded-pill.bg-primary
    span.fa.fa-bell
--- a/views/noscript/compiler.pug
+++ b/views/noscript/compiler.pug
@@ -6,7 +6,7 @@ block content
      input#filterAnsi(name='filterAnsi' value='true' type='hidden')

      .form-pair.inlined.dropdown
-        a.btn.nodropdown-toggle#outputDropdown(href="javascript:;" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false")
+        a.btn.nodropdown-toggle#outputDropdown(href="javascript:;" role="button" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false")
          span.fas.fa-cog
          | Output

@@ -14,7 +14,7 @@ block content
          include ../options-output.pug

      .form-pair.inlined.dropdown
-        a.btn.nodropdown-toggle#filtersDropdown(href="javascript:;" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false")
+        a.btn.nodropdown-toggle#filtersDropdown(href="javascript:;" role="button" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false")
          span.fas.fa-filter
          | Filters

--- a/views/noscript/footer.pug
+++ b/views/noscript/footer.pug
@@ -1,7 +1,7 @@
 block footer
  nav.bg-light
    if mobileViewer
-      a.btn.nodropdown-toggle#otherDropdown(href="javascript:;" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false") Other
+      a.btn.nodropdown-toggle#otherDropdown(href="javascript:;" role="button" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false") Other

    .noscriptdropdown(aria-labelledby="otherDropdown")
      include ../menu-other.pug
--- a/views/noscript/header.pug
+++ b/views/noscript/header.pug
@@ -1,11 +1,11 @@
 .header
  nav.navbar.navbar-godbolt.navbar-expand-md.navbar-light.bg-light
    include ../logo.pug
-    #motd.navbar-nav.navbar-center.mr-auto.community-advert.d-none
+    #motd.navbar-nav.navbar-center.me-auto.community-advert.d-none
      span.content
      | Thanks for using Compiler Explorer
    .navbar-nav.navbar-right
      if showSponsors
-        li.nav-item.btn.btn-outline-primary#ces(data-toggle="modal")
+        li.nav-item.btn.btn-outline-primary#ces(data-bs-toggle="modal")
          a(href=`${httpRoot}noscript/sponsors`) Sponsors
          include ../sponsor-icons.pug
--- a/views/noscript/languages.pug
+++ b/views/noscript/languages.pug
@@ -1,7 +1,7 @@
 block header
  nav.bg-light
    if mobileViewer
-      a.btn.nodropdown-toggle#languageDropdown(href="javascript:;" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false") Language
+      a.btn.nodropdown-toggle#languageDropdown(href="javascript:;" role="button" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false") Language

    .noscriptdropdown(aria-labelledby="languageDropdown")
      each language in languages
--- a/views/popups/alert.pug
+++ b/views/popups/alert.pug
@@ -3,9 +3,7 @@
    .modal-content
      .modal-header
        h5.modal-title Something alert worthy
-        button.close(type="button" data-dismiss="modal" aria-hidden="true" aria-label="Close")
-          span(aria-hidden="true")
-            | &times;
+        button.btn-close(type="button" data-bs-dismiss="modal" aria-hidden="true" aria-label="Close")
      .modal-body
      .modal-footer
-        button.btn.btn-outline-primary(type="button" data-dismiss="modal" data-cy="close-alert-btn") Close
+        button.btn.btn-outline-primary(type="button" data-bs-dismiss="modal" data-cy="close-alert-btn") Close
--- a/views/popups/compiler-picker-modal.pug
+++ b/views/popups/compiler-picker-modal.pug
@@ -3,9 +3,7 @@
    .modal-content
      .modal-header
        h5.modal-title Compilers
-        button.close(type="button" data-dismiss="modal" aria-hidden="true" aria-label="Close")
-          span(aria-hidden="true")
-            | &times;
+        button.btn-close(type="button" data-bs-dismiss="modal" aria-hidden="true" aria-label="Close")
      .modal-body
        .card
          .card-body
--- a/views/popups/enter-something.pug
+++ b/views/popups/enter-something.pug
@@ -3,12 +3,11 @@
    .modal-content
      .modal-header
        h5.modal-title Enter something here
-        button.close(type="button" data-dismiss="modal" aria-hidden="true" aria-label="Close")
-          span(aria-hidden="true")
-            | &times;
+        button.btn-close(type="button" data-bs-dismiss="modal" aria-hidden="true" aria-label="Close")
      .modal-body
-        .question
-        input.question-answer
+        .mb-3
+          label.form-label.question
+          input.form-control.question-answer
      .modal-footer
-        button.btn.btn-light.no(type="button" data-dismiss="modal") Cancel
-        button.btn.btn-light.yes(type="button" data-dismiss="modal") Ok
+        button.btn.btn-light.no(type="button" data-bs-dismiss="modal") Cancel
+        button.btn.btn-light.yes(type="button" data-bs-dismiss="modal") Ok
--- a/views/popups/history.pug
+++ b/views/popups/history.pug
@@ -3,9 +3,7 @@
    .modal-content
      .modal-header
        h5.modal-title History
-        button.close(type="button" data-dismiss="modal" aria-hidden="true" aria-label="Close")
-          span(aria-hidden="true")
-            | &times;
+        button.btn-close(type="button" data-bs-dismiss="modal" aria-hidden="true" aria-label="Close")
      .modal-body
        .card
          .card-body
@@ -18,4 +16,4 @@
              div.src-content#load-history-src-display(style="height:600px;overflow-y:scroll;flex:2")
                div.monaco-placeholder
      .modal-footer
-        button.btn.btn-outline-primary(type="button" data-dismiss="modal") Close
+        button.btn.btn-outline-primary(type="button" data-bs-dismiss="modal") Close
--- a/views/popups/library-selection.pug
+++ b/views/popups/library-selection.pug
@@ -3,9 +3,7 @@
    .modal-content
      .modal-header
        h5.modal-title Libraries
-        button.close(type="button" data-dismiss="modal" aria-hidden="true" aria-label="Close")
-          span(aria-hidden="true")
-            | &times;
+        button.btn-close(type="button" data-bs-dismiss="modal" aria-hidden="true" aria-label="Close")
      .modal-body
        .card
          .card-body
@@ -13,8 +11,9 @@
              .row
                .col-lg
                  div(style='text-align: center')
-                    input.lib-search-input(value="" placeholder="Search text")
-                    button.btn.btn-primary.lib-search-button(type="button") Search
+                    .input-group.mb-3
+                      input.form-control.lib-search-input(value="" placeholder="Search text")
+                      button.btn.btn-primary.lib-search-button(type="button") Search
                    hr
              .row
                .col-lg.libs-how-to-use
--- a/views/popups/load-save.pug
+++ b/views/popups/load-save.pug
@@ -3,17 +3,15 @@
    .modal-content(style="max-width: unset")
      .modal-header
        h5.modal-title Load and save editor text
-        button.close(type="button" data-dismiss="modal" aria-hidden="true" aria-label="Close")
-          span(aria-hidden="true")
-            | &times;
+        button.btn-close(type="button" data-bs-dismiss="modal" aria-label="Close")
      .modal-body
        .card
          .card-header
            ul.nav.nav-tabs.card-header-tabs(role="tablist")
-              li.nav-item(role="presentation"): a.nav-link.active(href="#load-examples" role="tab" data-toggle="tab") Examples
-              li.nav-item(role="presentation"): a.nav-link(href="#load-browser-local" role="tab" data-toggle="tab") Browser-local storage
-              li.nav-item(role="presentation"): a.nav-link(href="#load-browser-local-history" role="tab" data-toggle="tab") Browser-local history
-              li.nav-item(role="presentation"): a.nav-link(href="#load-file-system" role="tab" data-toggle="tab") File system
+              li.nav-item(role="presentation"): a.nav-link.active(href="#load-examples" role="tab" data-bs-toggle="tab") Examples
+              li.nav-item(role="presentation"): a.nav-link(href="#load-browser-local" role="tab" data-bs-toggle="tab") Browser-local storage
+              li.nav-item(role="presentation"): a.nav-link(href="#load-browser-local-history" role="tab" data-bs-toggle="tab") Browser-local history
+              li.nav-item(role="presentation"): a.nav-link(href="#load-file-system" role="tab" data-bs-toggle="tab") File system
          .card-body.tab-content
            #load-examples.tab-pane.active(role="tabpanel")
              h4.card-title Load from examples:
@@ -23,26 +21,26 @@
              h4.card-title Load from browser-local storage:
              ul.local-storage.small-v-scrollable
                li.template
-                  a.mr-3(href="javascript:;")
-                  button.overwrite.btn.btn-sm.btn-light.mr-1
-                    span.fa.fa-edit.mr-1
+                  a.me-3(href="javascript:;")
+                  button.overwrite.btn.btn-sm.btn-light.me-1
+                    span.fa.fa-edit.me-1
                    | Overwrite
                  button.delete.btn.btn-sm.btn-light
-                    span.fa.fa-trash.mr-1
+                    span.fa.fa-trash.me-1
                    | Delete
-              .input-group
-                input.save-name(type="text" size="20" placeholder="Set name of state")
-                .input-group-append
-                  button.btn.btn-light.save-button(type="button") Save to browser-local storage
+              .input-group.mb-3
+                input.form-control.save-name(type="text" placeholder="Set name of state")
+                button.btn.btn-light.save-button(type="button") Save to browser-local storage
            #load-browser-local-history.tab-pane(role="tabpanel")
              h4.card-title Load from browser-local history:
              ul.local-history.small-v-scrollable
                li.template: a(href="javascript:;")
            #load-file-system.tab-pane(role="tabpanel")
              h4.card-title Load/save to your system
-              label.btn.btn-outline-secondary.btn-file(role="button") Load from a local file
-                input.local-file(type="file")
-              label.btn.btn-outline-secondary.btn-file.save-btn(role="button") Save to file
-                input.save-file(type="button")
+              .mb-3
+                label.form-label Load from a local file
+                input.form-control.local-file(type="file")
+              .mb-3
+                button.btn.btn-outline-secondary.save-btn(type="button") Save to file
      .modal-footer
-        button.btn.btn-outline-primary(type="button" data-dismiss="modal" aria-label="Close") Close
+        button.btn.btn-outline-primary(type="button" data-bs-dismiss="modal" aria-label="Close") Close
--- a/views/popups/overrides-selection.pug
+++ b/views/popups/overrides-selection.pug
@@ -3,9 +3,7 @@
    .modal-content
      .modal-header
        h5.modal-title Compiler overrides
-        button.close(type="button" data-dismiss="modal" aria-hidden="true" aria-label="Close")
-          span(aria-hidden="true")
-            | &times;
+        button.btn-close(type="button" data-bs-dismiss="modal" aria-hidden="true" aria-label="Close")
      .modal-body
        .card
          .card-body
@@ -25,8 +23,8 @@
                        span.override-name Compiler environment variables
                      .card-body
                        span.description One environment variable per line, KEY=VALUE, that will be set during compilation.
-                        span.custom-override
-                          textarea.envvars(cols="30")
+                        span
+                          textarea.form-control.envvars(cols="30", rows="3")
                  .possible-overrides.items
                .overrides-favorites-col.col-md
                  h6 Favorites
--- a/views/popups/renamepanemodal.pug
+++ b/views/popups/renamepanemodal.pug
@@ -3,9 +3,7 @@
    .modal-content
      .modal-header
        h5.modal-title Rename Pane
-        button.close(type="button" data-dismiss="modal" aria-hidden="true" aria-label="Close")
-          span(aria-hidden="true")
-            | &times;
+        button.btn-close(type="button" data-bs-dismiss="modal" aria-hidden="true" aria-label="Close")
      .modal-body
        .card
          .card-body
@@ -13,5 +11,5 @@
              .input-group
                input#renamepaneinput.form-control.panename(type="text" placeholder="New pane name" size="1024")
      .modal-footer
-        button.btn.btn-outline-secondary(type="button" data-dismiss="modal") Close
-        button#renamepanesubmit.btn.btn-outline-primary(type="submit" data-dismiss="modal" value="Save Changes") Save Changes
+        button.btn.btn-outline-secondary(type="button" data-bs-dismiss="modal") Close
+        button#renamepanesubmit.btn.btn-outline-primary(type="submit" data-bs-dismiss="modal" value="Save Changes") Save Changes
--- a/views/popups/runtimetools-selection.pug
+++ b/views/popups/runtimetools-selection.pug
@@ -3,9 +3,7 @@
    .modal-content
      .modal-header
        h5.modal-title Runtime tools
-        button.close(type="button" data-dismiss="modal" aria-hidden="true" aria-label="Close")
-          span(aria-hidden="true")
-            | &times;
+        button.btn-close(type="button" data-bs-dismiss="modal" aria-hidden="true" aria-label="Close")
      .modal-body
        .card
          .card-body
@@ -23,8 +21,8 @@
                        span.runtimetool-name Runtime environment variables
                      .card-body
                        span.description One environment variable per line, KEY=VALUE.
-                        span.custom-runtimetool
-                          textarea.envvars(cols="30")
+                        span
+                          textarea.form-control.envvars(cols="30", rows="3")
                  .possible-runtimetools.items
                .runtimetools-favorites-col.col-md
                  h6 Favorites
--- a/views/popups/settings.pug
+++ b/views/popups/settings.pug
@@ -1,18 +1,17 @@
 mixin checkbox(cls, text)
-  .checkbox
-    label
-      input(class=cls type="checkbox")
-      != text
+  .form-check
+    input.form-check-input(class=cls type="checkbox" id="settings-checkbox-"+cls)
+    label.form-check-label(for="settings-checkbox-"+cls)!= text

 mixin select(cls, text)
-  div
-    label!= text
-    select(class=cls)
+  .mb-3
+    label.form-label(for="settings-select-"+cls)!= text
+    select.form-select(class=cls id="settings-select-"+cls)

 mixin input(cls, type, text, style)
-  div
-    label!= text
-    input(class=cls type=type style=style)
+  .mb-3
+    label.form-label(for="settings-input-"+cls)!= text
+    input.form-control(class=cls type=type style=style id="settings-input-"+cls)


 #settings.modal.fade.gl_keep(tabindex="-1" role="dialog")
@@ -21,8 +20,7 @@ mixin input(cls, type, text, style)
      .modal-header
        h5.modal-title
          | Compiler Explorer Settings
-        button.close(type="button" data-dismiss="modal" aria-label="Close")
-          span(aria-hidden="true") &times;
+        button.btn-close(type="button" data-bs-dismiss="modal" aria-label="Close")
      .modal-body
        .card
          .card-header
@@ -30,53 +28,54 @@ mixin input(cls, type, text, style)
            | preserved as part of shared URLs, and are persisted locally using browser
            | local storage.
            ul.nav.nav-tabs.card-header-tabs(role="tablist")
-              li.nav-item(role="presentation"): a.nav-link.active(href="#colouring" role="tab" data-toggle="tab") Colouring
-              li.nav-item(role="presentation"): a.nav-link(href="#site-behaviour" role="tab" data-toggle="tab") Site behaviour
-              li.nav-item(role="presentation"): a.nav-link(href="#keybindings" role="tab" data-toggle="tab") Keybindings
-              li.nav-item(role="presentation"): a.nav-link(href="#editor" role="tab" data-toggle="tab") Editor
-              li.nav-item(role="presentation"): a.nav-link(href="#compilation" role="tab" data-toggle="tab") Compilation
+              li.nav-item(role="presentation"): a.nav-link.active(href="#colouring" role="tab" data-bs-toggle="tab") Colouring
+              li.nav-item(role="presentation"): a.nav-link(href="#site-behaviour" role="tab" data-bs-toggle="tab") Site behaviour
+              li.nav-item(role="presentation"): a.nav-link(href="#keybindings" role="tab" data-bs-toggle="tab") Keybindings
+              li.nav-item(role="presentation"): a.nav-link(href="#editor" role="tab" data-bs-toggle="tab") Editor
+              li.nav-item(role="presentation"): a.nav-link(href="#compilation" role="tab" data-bs-toggle="tab") Compilation
          .card-body.tab-content
-            #colouring.tab-pane.active.form-group(role="group")
+            #colouring.tab-pane.active(role="group")
              +select("theme", "Site theme")
              +checkbox("colourise", "Colourise lines to show how the source maps to the output")
              +checkbox("alwaysEnableAllSchemes", "Make all colour schemes available regardless of theme")
              +select("colourScheme", "Line highlighting colour scheme")
-            #site-behaviour.tab-pane.form-group(role="group")
-              label
-                | Default language
-                small(style="margin-left: 3px")
-                  span.fas.fa-info-circle(title="New editors only (Reset UI to clear yours)" aria-label="New editors only (Reset UI to clear yours)")
-              select.defaultLanguage
+            #site-behaviour.tab-pane(role="group")
+              .mb-3
+                label.form-label(for="settings-select-defaultLanguage") Default language
+                  small(style="margin-left: 3px")
+                    span.fas.fa-info-circle(title="New editors only (Reset UI to clear yours)" aria-label="New editors only (Reset UI to clear yours)")
+                select.form-select.defaultLanguage(id="settings-select-defaultLanguage")
              +checkbox("keepMultipleTabs", "Keep page status per tab")
              +checkbox("allowStoreCodeDebug", "Allow my source code to be temporarily stored for diagnostic purposes in the event of an error")
              +checkbox("newEditorLastLang", "Use last selected language when opening new Editors")
              +checkbox("enableCommunityAds", "Show community events")
-            #keybindings.tab-pane.form-group(role="group")
+            #keybindings.tab-pane(role="group")
              +checkbox("useVim", "Vim editor mode")
              .the-save-option-to-auto-share
-                label
-                  kbd Ctrl
-                  | +
-                  kbd S
-                  | &nbsp;behaviour
-                select.enableCtrlS
-              .checkbox.the-save-option-to-tree-save
-                label
-                  input.enableCtrlStree(type="checkbox")
+                mb-3
+                  label.form-label(for="settings-checkbox-enableCtrlS")
+                    kbd Ctrl
+                    | +
+                    kbd S
+                    | &nbsp;behaviour
+                    select.form-select.enableCtrlS(id="settings-checkbox-enableCtrlS")
+              .form-check.the-save-option-to-tree-save
+                input.form-check-input.enableCtrlStree(type="checkbox" id="settings-checkbox-enableCtrlStree")
+                label.form-check-label(for="settings-checkbox-enableCtrlStree")
                  | Make
                  kbd Ctrl
                  | +
                  kbd S
                  | &nbsp;include and save the file to a Tree if that's added to the UI
-              .checkbox.the-popup-dialog-box-option
-                label
-                  input.enableSharingPopover(type="checkbox")
+              .form-check.the-popup-dialog-box-option
+                input.form-check-input.enableSharingPopover(type="checkbox" id="settings-checkbox-enableSharingPopover")
+                label.form-check-label(for="settings-checkbox-enableSharingPopover")
                  | Pop up a dialog box when
                  kbd Ctrl
                  | +
                  kbd S
                  | &nbsp; is set to create a short link.
-            #editor.tab-pane.form-group(role="group")
+            #editor.tab-pane(role="group")
              +input("editorsFFont", "text", "Desired Font Family in editors", "width:100%")
              +select("defaultFontScale", "Default font scale")
              +checkbox("editorsFLigatures", "Enable font ligatures")
@@ -97,19 +96,20 @@ mixin input(cls, type, text, style)
              +checkbox("wordWrap", "Enable Word Wrapping")
              +checkbox("enableCodeLens", "Enable CodeLens features (requires refresh to take effect)")
              +checkbox("colouriseBrackets", "Colourise matching bracket pairs")
-            #compilation.tab-pane.form-group(role="group")
+            #compilation.tab-pane(role="group")
              div
                +checkbox("compileOnChange", "Compile automatically when source changes")
                +checkbox("autoDelayBeforeCompile", "Use automatic delay before compiling")
                div
-                  label Delay before compiling:&nbsp;
-                    span.delay-current-value &nbsp;
-                  .slider-input
-                    b 0.25s
-                    input.delay(type="range")
-                    b 3s
+                  mb-3
+                    label.form-label(for="settings-input-delay") Delay before compiling:&nbsp;
+                      span.delay-current-value &nbsp;
+                    .slider-input(id="settings-input-delay")
+                      b 0.25s
+                      input.delay(type="range")
+                      b 3s
                +checkbox("formatOnCompile", "Enable formatting on compilation (for supported languages)")
                +checkbox("executorCompileOnChange", "Compile executor automatically when arguments change")
                +checkbox("shakeStatusIconOnWarnings", "Shake the status icon on argument warnings")
      .modal-footer
-        button.btn.btn-outline-primary(type="button" data-dismiss="modal") Close
+        button.btn.btn-outline-primary(type="button" data-bs-dismiss="modal") Close
--- a/views/popups/sharelinkdialog.pug
+++ b/views/popups/sharelinkdialog.pug
@@ -3,26 +3,23 @@
    .modal-content
      .modal-header
        h5.modal-title Share
-        button.close(type="button" data-dismiss="modal" aria-hidden="true" aria-label="Close")
-          span(aria-hidden="true")
-            | &times;
+        button.btn-close(type="button" data-bs-dismiss="modal" aria-hidden="true" aria-label="Close")
      .modal-body
        .card
          .card-body
            .container
+              label.form-label.visually-hidden(for="share-permalink") Share URL
              .input-group
-                input.form-control.permalink(type="text" placeholder="Loading" readonly size="1024")
-                .input-group-append
-                  button.btn.btn-outline-secondary.clippy(type="button" data-clipboard-target="#sharelinkdialog .permalink" title="Copy to clipboard")
-                    span.fa.fa-clipboard
-              #embedsettings.form-group(role="group")
-                .checkbox
-                  label
-                    input.readOnly(type="checkbox")
-                    | Read Only
-                .checkbox
-                  label
-                    input.hideEditorToolbars(type="checkbox")
-                    | Hide Editor Toolbars
+                input.form-control.permalink#share-permalink(type="text" placeholder="Loading" readonly size="1024" aria-describedby="share-permalink-help")
+                button.btn.btn-outline-secondary.clippy(type="button" data-clipboard-target="#sharelinkdialog .permalink" title="Copy to clipboard" aria-label="Copy to clipboard")
+                  span.fa.fa-clipboard
+              small.form-text.text-muted#share-permalink-help Use this URL to share your code with others
+              #embedsettings.mb-3(role="group")
+                .form-check
+                  input.form-check-input.readOnly(type="checkbox" id="share-checkbox-readonly")
+                  label.form-check-label(for="share-checkbox-readonly") Read Only
+                .form-check
+                  input.form-check-input.hideEditorToolbars(type="checkbox" id="share-checkbox-hideEditorToolbars")
+                  label.form-check-label(for="share-checkbox-hideEditorToolbars") Hide Editor Toolbars
              if sharingEnabled
                .socialsharing.mt-2
--- a/views/popups/site-template-loader.pug
+++ b/views/popups/site-template-loader.pug
@@ -3,9 +3,7 @@
    .modal-content
      .modal-header
        h5.modal-title Load Site Template
-        button.close(type="button" data-dismiss="modal" aria-hidden="true" aria-label="Close")
-          span(aria-hidden="true")
-            | &times;
+        button.btn-close(type="button" data-bs-dismiss="modal" aria-hidden="true" aria-label="Close")
      .modal-body
        .container
          .row(id="site-template-modal-row")
--- a/views/popups/timing.pug
+++ b/views/popups/timing.pug
@@ -3,10 +3,8 @@
    .modal-content
      .modal-header
        h5.modal-title Timing
-        button.close(type="button" data-dismiss="modal" aria-hidden="true" aria-label="Close")
-          span(aria-hidden="true")
-            | &times;
+        button.btn-close(type="button" data-bs-dismiss="modal" aria-hidden="true" aria-label="Close")
      .modal-body
        #chart
      .modal-footer
-        button.btn.btn-outline-primary(type="button" data-dismiss="modal") Close
+        button.btn.btn-outline-primary(type="button" data-bs-dismiss="modal") Close
--- a/views/popups/yes-no.pug
+++ b/views/popups/yes-no.pug
@@ -3,10 +3,8 @@
    .modal-content
      .modal-header
        h5.modal-title Well, do you or not?
-        button.close(type="button" data-dismiss="modal" aria-hidden="true" aria-label="Close")
-          span(aria-hidden="true")
-            | &times;
+        button.btn-close(type="button" data-bs-dismiss="modal" aria-hidden="true" aria-label="Close")
      .modal-body
      .modal-footer
-        button.btn.btn-link.no(type="button" data-dismiss="modal") No
-        button.btn.btn-link.yes(type="button" data-dismiss="modal") Yes
+        button.btn.btn-link.no(type="button" data-bs-dismiss="modal") No
+        button.btn.btn-link.yes(type="button" data-bs-dismiss="modal") Yes
--- a/views/templates/panes/cfg.pug
+++ b/views/templates/panes/cfg.pug
@@ -3,7 +3,7 @@
    .btn-group.btn-group-sm(role="group")
      select.function-selector
    .btn-group.btn-group-sm(role="group" aria-label="CFG Export")
-      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="LLVM Opt Pass Options" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Set output options")
+      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="LLVM Opt Pass Options" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Set output options")
        span.fas.fa-arrow-down
        span.hideable Export
      .dropdown-menu
--- a/views/templates/panes/clangir.pug
+++ b/views/templates/panes/clangir.pug
@@ -8,7 +8,7 @@ mixin optionButton(bind, isActive, text, title)
  .top-bar.btn-toolbar.bg-light(role="toolbar")
    include ../../font-size
    .btn-group.btn-group-sm.options(role="group")
-      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="ClangIR Options" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Set output options")
+      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="ClangIR Options" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Set output options")
        span.fas.fa-anchor
        span.hideable Options
      .dropdown-menu
--- a/views/templates/panes/codeEditor.pug
+++ b/views/templates/panes/codeEditor.pug
@@ -10,7 +10,7 @@ mixin newPaneButton(classId, text, title, label, icon)
      button.btn.btn-sm.btn-light.load-save(title="Load or save text" aria-label="Load or save text")
        span.fa.fa-save
        span.hideable Save/Load
-      button.dropdown-toggle.btn.btn-sm.btn-light.add-pane(type="button" title="Add a new pane" aria-label="Add a new pane" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" data-cy="new-editor-dropdown-btn")
+      button.dropdown-toggle.btn.btn-sm.btn-light.add-pane(type="button" title="Add a new pane" aria-label="Add a new pane" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false" data-cy="new-editor-dropdown-btn")
        span.fa.fa-plus
        span.hideable Add new...
      .dropdown-menu(data-cy="new-editor-pane-dropdown")
@@ -18,7 +18,7 @@ mixin newPaneButton(classId, text, title, label, icon)
        +newPaneButton("add-executor", "Execution Only", "Add a new executor for this source", "New executor", "fas fa-microchip")
        +newPaneButton("conformance", "Conformance View", "Add a new conformance view", "New conformance view", "fa fa-list")
        +newPaneButton("add-editor", "Source Editor", "Add a new source editor", "New source editor", "fa fa-code")
-      button#vim-flag.btn.btn-sm.btn-light(title="Toggle Vim Keybindings")
+      button.vim-flag.btn.btn-sm.btn-light(title="Toggle Vim Keybindings")
        span.fab.fa-vimeo-v
        span.hideable Vim
    if thirdPartyIntegrationEnabled
@@ -35,10 +35,10 @@ mixin newPaneButton(classId, text, title, label, icon)
      button.btn.btn-sm.btn-outline-info.ctrlSNothing(disabled=true style="display: none")
        span.fas.fa-smile

-    .btn-group.btn-group-sm.ml-auto(role="group" aria-label="Editor language")
+    .btn-group.btn-group-sm.ms-auto(role="group" aria-label="Editor language")
      button.btn.btn-sm.language-info
        span.fas.fa-info
      select.change-language(title="Change this editor's (and associated panels) language" placeholder="Language" disabled=embedded && readOnly)
  div.currentCursorPosition
-  div#v-status
+  div.v-status
  .monaco-placeholder
--- a/views/templates/panes/compiler-output.pug
+++ b/views/templates/panes/compiler-output.pug
@@ -10,4 +10,4 @@
      button.btn.btn-sm.btn-light.select-all(type="button" title="Select all lines")
        span.fa.fa-align-justify(style="border: 1px dotted white;border-radius: 0.125em;padding: 2px")
        span.hideable Select all
-  pre.content.output-content
+  pre.content.output-content(aria-live="polite" role="log" aria-label="Compiler output")
--- a/views/templates/panes/compiler.pug
+++ b/views/templates/panes/compiler.pug
@@ -7,34 +7,30 @@ mixin newPaneButton(classId, text, title, icon)
  .top-bar.btn-toolbar.bg-light(role="toolbar")
    .btn-group.btn-group-sm(role="group" aria-label="Compiler picker")
      .input-group
-        .input-group-prepend
-          .input-group
-            select.compiler-picker
-            .input-group-append
-              button.btn.btn-sm.btn-light.input-group-text.picker-popout-button(data-trigger="click" style="cursor: pointer;" role="button" title="Compiler picker popout")
-                span
-                 i.fa-solid.fa-arrow-up-right-from-square
-            .input-group-append
-              button.btn.btn-sm.btn-light.input-group-text.prepend-options(data-trigger="click" style="cursor: pointer;" role="button" title="All compilation options")
-                span.status-icon
-        input.options.form-control(type="text" placeholder="Compiler options..." size="256" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false")
-        .input-group-append.populararguments(title="Popular arguments")
-          button.btn.btn-sm.btn-light.btn-outline-secondary.dropdown-toggle.dropdown-toggle-split.popular-arguments-btn(type="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false")
-            span.sr-only Popular arguments
-          div.dropdown-menu.dropdown-menu-right
+        select.compiler-picker
+        button.btn.btn-sm.btn-light.input-group-text.picker-popout-button(data-trigger="click" style="cursor: pointer;" role="button" title="Compiler picker popout")
+          span
+            i.fa-solid.fa-arrow-up-right-from-square
+        button.btn.btn-sm.btn-light.input-group-text.prepend-options(data-trigger="click" style="cursor: pointer;" role="button" title="All compilation options")
+          span.status-icon
+        input.options.form-control(type="text" placeholder="Compiler options..." size="256" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false" aria-label="Compiler options")
+        .populararguments(title="Popular arguments")
+          button.btn.btn-sm.btn-light.btn-outline-secondary.dropdown-toggle.dropdown-toggle-split.popular-arguments-btn(type="button" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false")
+            span.visually-hidden Popular arguments
+          div.dropdown-menu.dropdown-menu-end
            button.dropdown-item.btn.btn-light.btn-sm
              .argmenuitem
                span.argtitle Detailed Compiler Flags
                span.argdescription Open a new window to edit verbose compiler flags
    include ../../font-size
    .btn-group.btn-group-sm.filters(role="group")
-      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="Compiler output options" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Change how the compiler's output is generated")
+      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="Compiler output options" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Change how the compiler's output is generated")
        span.fas.fa-cog
        span.hideable Output...
      .dropdown-menu
        include ../../options-output
    .btn-group.btn-group-sm.filters(role="group")
-      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="Compiler output filters" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Change how the compiler output is filtered")
+      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="Compiler output filters" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Change how the compiler output is filtered")
        span.fas.fa-filter
        span.hideable Filter...
      .dropdown-menu
@@ -48,10 +44,10 @@ mixin newPaneButton(classId, text, title, icon)
        span.fas.fa-wrench
        span.dp-text.hideable Overrides
    .btn-group.btn-group-sm(role="group")
-      button.btn.btn-sm.btn-light.dropdown-toggle.add-pane(type="button" title="Add a new pane" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Add new element for this compiler" data-cy="new-compiler-dropdown-btn")
+      button.btn.btn-sm.btn-light.dropdown-toggle.add-pane(type="button" title="Add a new pane" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Add new element for this compiler" data-cy="new-compiler-dropdown-btn")
        span.fas.fa-plus
        span.hideable Add new...
-      .dropdown-menu.dropdown-menu-right.new-pane-dropdown(data-cy="new-compiler-pane-dropdown")
+      .dropdown-menu.dropdown-menu-end.new-pane-dropdown(data-cy="new-compiler-pane-dropdown")
        +newPaneButton("add-compiler", "Clone Compiler", "Clone this compiler window (click or drag)", "far fa-clone")
        +newPaneButton("create-executor", "Executor From This", "Create executor from this compiler", "fas fa-microchip")
        +newPaneButton("view-optimization", "Opt Remarks", "Show optimization remarks", "fas fa-weight")
@@ -73,22 +69,21 @@ mixin newPaneButton(classId, text, title, icon)
        +newPaneButton("view-gnatdebug", "GNAT Debug Expanded Code", "Show GNAT debug expanded code", "fas fa-tree")
        +newPaneButton("view-cfg", "Control Flow Graph", "Show assembly control flow graphs", "fas fa-exchange-alt")
    .btn-group.btn-group-sm(role="group")
-      button.btn.btn-sm.btn-light.dropdown-toggle.add-tool(type="button" title="Add tool" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Add tooling to this editor and compiler")
+      button.btn.btn-sm.btn-light.dropdown-toggle.add-tool(type="button" title="Add tool" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Add tooling to this editor and compiler")
        span.fas.fa-screwdriver
        span.hideable Add tool...
-      .dropdown-menu.dropdown-menu-right.new-tool-dropdown
+      .dropdown-menu.dropdown-menu-end.new-tool-dropdown
  .monaco-placeholder
  .bottom-bar.bg-light
    if !embedded
      .btn-group.btn-group-sm
        .input-group
-          .input-group-prepend
-            button.btn.btn-sm.btn-light.clear-cache(title="Clear cache & recompile")
-              span.fas.fa-redo
-          button.btn.btn-sm.btn-light.output-btn(data-cy="new-output-pane-btn")
+          button.btn.btn-sm.btn-light.clear-cache(title="Clear cache & recompile" aria-label="Clear cache and recompile")
+            span.fas.fa-redo
+          button.btn.btn-sm.btn-light.output-btn(data-cy="new-output-pane-btn" aria-label="Show compiler output")
            span.fas.fa-receipt.status-text
            | &nbsp;Output
-            span.output-count
+            span.output-count(aria-live="polite")
              | &nbsp;(
              span.text-count
                | 0
@@ -96,11 +91,11 @@ mixin newPaneButton(classId, text, title, icon)
              span.err-count
                | 0
              | )
-      span.short-compiler-name.mr-1
-      button.btn.btn-sm.btn-light.full-compiler-name(data-trigger="click" style="cursor: pointer;" role="button")
+      span.short-compiler-name.me-1(aria-hidden="true")
+      button.btn.btn-sm.btn-light.full-compiler-name(data-trigger="click" style="cursor: pointer;" role="button" aria-label="Show compiler information")
        span.fas.fa-info
-      span.compile-info.mr-1(title="Compilation info")
-      button.btn.btn-sm.btn-light.full-timing-info(data-trigger="click" style="cursor: pointer;" role="button")
+      span.compile-info.me-1(title="Compilation info" aria-label="Compilation information")
+      button.btn.btn-sm.btn-light.full-timing-info(data-trigger="click" style="cursor: pointer;" role="button" aria-label="Show full timing information")
        span.fas.fa-chart-bar
-      button.btn.btn-sm.btn-light.compiler-license(data-trigger="click" style="cursor: pointer;" role="button")
+      button.btn.btn-sm.btn-light.compiler-license(data-trigger="click" style="cursor: pointer;" role="button" aria-label="View compiler license")
        span Compiler License
--- a/views/templates/panes/device.pug
+++ b/views/templates/panes/device.pug
@@ -2,5 +2,5 @@
  .top-bar.btn-toolbar.bg-light(role="toolbar")
    include ../../font-size
    .btn-group.btn-group-sm(role="group")
-      select.change-device(placeholder="Select a device...")
+      select.form-select.change-device(placeholder="Select a device...")
  .monaco-placeholder
--- a/views/templates/panes/diff.pug
+++ b/views/templates/panes/diff.pug
@@ -1,18 +1,16 @@
 #diff
-  .top-bar.btn-toolbar.bg-light(role="toolbar")
+  .top-bar.btn-toolbar.bg-light.py-1.d-flex.align-items-center(role="toolbar")
    include ../../font-size
-    .btn-group.btn-group-sm
-      .input-group.input-group-sm.mb-auto
-        .input-group-prepend
-          label.input-group-text
-            | Left:&nbsp;
+    .btn-group.btn-group-sm.flex-grow-1.me-2
+      .input-group.input-group-sm.w-100
+        label.input-group-text
+          | Left:&nbsp;
        select.diff-picker.lhs(placeholder="Select compiler...")
        select.difftype-picker.lhsdifftype(placeholder="...")
-    .btn-group.btn-group-sm.ml-4
-      .input-group.input-group-sm.mb-auto
-        .input-group-prepend
-          label.input-group-text
-            | Right:&nbsp;
+    .btn-group.btn-group-sm.flex-grow-1
+      .input-group.input-group-sm.w-100
+        label.input-group-text
+          | Right:&nbsp;
        select.diff-picker.rhs(placeholder="Select compiler...")
        select.difftype-picker.rhsdifftype(placeholder="...")
  .monaco-placeholder
--- a/views/templates/panes/executor.pug
+++ b/views/templates/panes/executor.pug
@@ -30,40 +30,37 @@
  .top-bar.btn-toolbar.bg-light.panel-compilation(role="toolbar")
    .btn-group.btn-group-sm(role="group" aria-label="Compiler picker")
      .input-group
-        .input-group-prepend
-          .input-group
-            select.compiler-picker
-            .input-group-append
-              button.btn.btn-sm.btn-light.input-group-text.picker-popout-button(data-trigger="click" style="cursor: pointer;" role="button" title="Compiler picker popout")
-                span
-                 i.fa-solid.fa-arrow-up-right-from-square
-            .input-group-append
-              button.btn.btn-sm.btn-light.input-group-text.prepend-options(data-trigger="click" style="cursor: pointer;" role="button" title="All compilation options")
-                span.btn.btn-sm.btn-light.status-icon
-        input.compilation-options.form-control(type="text" placeholder="Compiler options..." size="256" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false")
+        select.compiler-picker
+        button.btn.btn-sm.btn-light.input-group-text.picker-popout-button(data-trigger="click" style="cursor: pointer;" role="button" title="Compiler picker popout")
+          span
+            i.fa-solid.fa-arrow-up-right-from-square
+        button.btn.btn-sm.btn-light.input-group-text.prepend-options(data-trigger="click" style="cursor: pointer;" role="button" title="All compilation options")
+          span.btn.btn-sm.btn-light.status-icon
+        label.visually-hidden(for="compilation-options") Compiler options for execution
+        input.compilation-options.form-control#compilation-options(type="text" placeholder="Compiler options..." size="256" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false" aria-label="Compiler options for execution")
        // TODO: Maybe enable this in the future?
-        //.input-group-append.populararguments(title="Popular arguments")
-          button.btn.btn-sm.btn-light.btn-outline-secondary.dropdown-toggle.dropdown-toggle-split.popular-arguments-btn(type="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false")
-            span.sr-only Popular arguments
-          div.dropdown-menu.dropdown-menu-right
+        //.populararguments(title="Popular arguments")
+          button.btn.btn-sm.btn-light.btn-outline-secondary.dropdown-toggle.dropdown-toggle-split.popular-arguments-btn(type="button" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false")
+            span.visually-hidden Popular arguments
+          div.dropdown-menu.dropdown-menu-end
            button.dropdown-item.btn.btn-light.btn-sm
              .argmenuitem
                span.argtitle Detailed Compiler Flags
                span.argdescription Open a new window to edit verbose compiler flags
  .top-bar.btn-toolbar.bg-light.panel-args.d-none(role="toolbar")
-    input.execution-arguments.form-control(type="text" placeholder="Execution arguments..." size="256" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false")
+    input.execution-arguments.form-control(type="text" placeholder="Execution arguments..." size="256" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false" aria-label="Execution arguments")
  .top-bar.btn-toolbar.bg-light.panel-stdin.d-none(role="toolbar")
-    textarea.execution-stdin.form-control(placeholder="Execution stdin..." cols="1024" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false" aria-multiline="false" style="resize: vertical")
+    textarea.execution-stdin.form-control(placeholder="Execution stdin..." cols="1024" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false" aria-multiline="true" style="resize: vertical" aria-label="Standard input for program execution")
  pre.content
-    .execution-status
-    .compiler-output
-    .execution-output
+    .execution-status(aria-live="polite" role="status" aria-label="Execution status")
+    .compiler-output(aria-live="polite" role="log" aria-label="Compiler output")
+    .execution-output(aria-live="polite" role="log" aria-label="Program execution output")
  .bottom-bar.bg-light
-    button.btn.btn-sm.btn-light.rerun(title="Rerun")
+    button.btn.btn-sm.btn-light.rerun(title="Rerun" aria-label="Rerun execution")
      span.fas.fa-circle-play
-    button.btn.btn-sm.btn-light.clear-cache(title="Clear cache & recompile")
+    button.btn.btn-sm.btn-light.clear-cache(title="Clear cache & recompile" aria-label="Clear cache and recompile")
      span.fas.fa-redo
-    span.short-compiler-name
-    button.btn.btn-sm.btn-light.fas.fa-info.full-compiler-name(data-trigger="click" style="cursor: pointer;" role="button")
-    span.compile-time(title="Compilation time (Result size)")
-    button.btn.btn-sm.btn-light.fas.fa-chart-bar.full-timing-info(data-trigger="click" style="cursor: pointer;" role="button")
+    span.short-compiler-name(aria-hidden="true")
+    button.btn.btn-sm.btn-light.fas.fa-info.full-compiler-name(data-trigger="click" style="cursor: pointer;" role="button" aria-label="Show compiler info")
+    span.compile-time(title="Compilation time (Result size)" aria-label="Compilation time and result size")
+    button.btn.btn-sm.btn-light.fas.fa-chart-bar.full-timing-info(data-trigger="click" style="cursor: pointer;" role="button" aria-label="Show full timing information")
--- a/views/templates/panes/gccdump.pug
+++ b/views/templates/panes/gccdump.pug
@@ -10,7 +10,7 @@ mixin optionButton(bind, isActive, text, title)
    .btn-group.btn-group-sm(role="group")
      select.gccdump-pass-picker(placeholder="Select a pass...")
    .btn-group.btn-group-sm.dump-filters
-      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="Dump passes" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Available dump passes")
+      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="Dump passes" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Available dump passes")
        span.fas.fa-compass
        span.hideable Passes
      .dropdown-menu
@@ -18,7 +18,7 @@ mixin optionButton(bind, isActive, text, title)
        +optionButton("rtlDump", true, "RTL Pass", "Show RTL passes")
        +optionButton("ipaDump", true, "IPA Pass", "Show IPA passes")
    .btn-group.btn-group-sm.dump-filters
-      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="Dump pass options" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Control the details of the dump")
+      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="Dump pass options" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Control the details of the dump")
        span.fas.fa-microchip
        span.hideable Options
      .dropdown-menu
--- a/views/templates/panes/ir.pug
+++ b/views/templates/panes/ir.pug
@@ -13,14 +13,14 @@ mixin optionButton(bind, isActive, text, title)
          span Wrap lines
        input.d-none(type="checkbox" checked=false)
    .btn-group.btn-group-sm.options(role="group")
-      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="LLVM Opt Pass Options" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Set output options")
+      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="LLVM Opt Pass Options" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Set output options")
        span.fas.fa-anchor
        span.hideable Options
      .dropdown-menu
        +optionButton("demangle-symbols", true, "Demangle Symbols", "Demangle symbols")
        +optionButton("-fno-discard-value-names", true, "-fno-discard-value-names", "Keep value names instead of LLVM value numbers")
    .btn-group.btn-group-sm.filters(role="group")
-      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="LLVM Opt Pass Filters" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Set output filters")
+      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="LLVM Opt Pass Filters" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Set output filters")
        span.fas.fa-filter
        span.hideable Filters
      .dropdown-menu
--- a/views/templates/panes/opt-pipeline.pug
+++ b/views/templates/panes/opt-pipeline.pug
@@ -8,7 +8,7 @@ mixin optionButton(bind, isActive, text, title)
  .top-bar.btn-toolbar.bg-light(role="toolbar")
    include ../../font-size
    .btn-group.btn-group-sm.options(role="group")
-      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="Opt Pass Options" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Set output options")
+      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="Opt Pass Options" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Set output options")
        span.fas.fa-anchor
        span.hideable Options
      .dropdown-menu
@@ -16,7 +16,7 @@ mixin optionButton(bind, isActive, text, title)
        +optionButton("demangle-symbols", true, "Demangle Symbols", "Demangle symbols")
        +optionButton("-fno-discard-value-names", true, "-fno-discard-value-names", "Keep value names instead of LLVM value numbers")
    .btn-group.btn-group-sm.filters(role="group")
-      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="Opt Pass Filters" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Set output filters")
+      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="Opt Pass Filters" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Set output filters")
        span.fas.fa-filter
        span.hideable Filters
      .dropdown-menu
@@ -26,9 +26,8 @@ mixin optionButton(bind, isActive, text, title)
        //- +optionButton("library-functions", true, "Filter Library Functions", "Filter library functions")
    .btn-group.btn-group-sm
      .input-group.input-group-sm.mb-auto
-        .input-group-prepend
-          label.input-group-text.opt-group-name
-            | Function:&nbsp;
+        label.input-group-text.opt-group-name
+          | Function:&nbsp;
        select.opt-group-picker.group-selector(placeholder="Select group")
  div.opt-pipeline-body
    .passes-column(style="width: 250px;") Passes:
--- a/views/templates/panes/opt-view.pug
+++ b/views/templates/panes/opt-view.pug
@@ -14,7 +14,7 @@ mixin optionButton(bind, isActive, text, title)
        input.d-none(type="checkbox" checked=false)
    // TODO: Options -  display inlining context, color token (from col-num), remove duplicates
    .btn-group.btn-group-sm.filters(role="group")
-      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="Opt-Remarks Filters" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Set output filters")
+      button.btn.btn-sm.btn-light.dropdown-toggle(type="button" title="Opt-Remarks Filters" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false" aria-label="Set output filters")
        span.fas.fa-filter
        span.hideable Filters
      .dropdown-menu
--- a/views/templates/panes/tree.pug
+++ b/views/templates/panes/tree.pug
@@ -1,7 +1,7 @@
 #tree
  .top-bar.btn-toolbar.bg-light.mainbar(role="toolbar")
    .btn-group.btn-group-sm.menu(role="group" aria-label="Menu")
-      button.dropdown-toggle.btn.btn-sm.btn-light.file-menu(type="button" title="File" aria-label="File" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false")
+      button.dropdown-toggle.btn.btn-sm.btn-light.file-menu(type="button" title="File" aria-label="File" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false")
        span.fa.fa-save
        span.hideable Project
      .dropdown-menu
@@ -10,7 +10,7 @@
          span.dropdown-icon.fa.fa-save
          | Save
    .btn-group.btn-group-sm.options(role="group" aria-label="Tree settings")
-      button.dropdown-toggle.btn.btn-sm.btn-light.add-pane(type="button" title="Add a new pane" aria-label="Add a new pane" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false")
+      button.dropdown-toggle.btn.btn-sm.btn-light.add-pane(type="button" title="Add a new pane" aria-label="Add a new pane" data-bs-toggle="dropdown" aria-haspopup="true" aria-expanded="false")
        span.fa.fa-plus
        span.hideable Add new...
      .dropdown-menu
@@ -27,19 +27,19 @@
        button.btn.btn-sm.btn-light.cmake-project(type="button" title="CMake project" data-bind="isCMakeProject" aria-pressed="false" aria-label="CMake project")
          span CMake
        input.d-none(type="checkbox" checked=false)
-    .btn-group.btn-group-sm.ml-auto(role="group" aria-label="Language")
+    .btn-group.btn-group-sm.ms-auto(role="group" aria-label="Language")
      select.change-language(title="Change the language" placeholder="Language" disabled=embedded && readOnly)
  .top-bar.btn-toolbar.bg-light.panel-args.d-none(role="toolbar")
    input.cmake-arguments.form-control(type="text" placeholder="CMake arguments..." size="256" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false")
  .top-bar.btn-toolbar.bg-light.panel-outputfile.d-none(role="toolbar")
    input.cmake-customOutputFilename.form-control(type="text" placeholder="output.s" size="256" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false")
  .tree.v-scroll
-    ul.list-group
+    ul.list-group.list-group-flush
      li.root.list-group-item.far-fa-folder
        .group-header Included files
-        ul.list-group.named-editors
+        ul.list-group.list-group-flush.named-editors
      li.root.list-group-item.far-fa-folder
        .group-header Excluded files
-        ul.list-group.unnamed-editors
+        ul.list-group.list-group-flush.unnamed-editors
      li.drophere.row.align-items-center(style="display: none;")
        span.col-lg.text-center Drop files here
--- a/views/templates/widgets/compiler-selector.pug
+++ b/views/templates/widgets/compiler-selector.pug
@@ -1,19 +1,14 @@
 #compiler-selector
-  .form-row
+  .row
    .input-group
-      .input-group-prepend
-        .input-group
-          select.compiler-picker
-          .input-group-append
-              button.btn.btn-sm.btn-light.input-group-text.picker-popout-button(data-trigger="click" style="cursor: pointer;" role="button" title="Compiler picker popout")
-                span
-                 i.fa-solid.fa-arrow-up-right-from-square
-          .input-group-append
-            button.btn.btn-sm.btn-light.input-group-text.prepend-options(tabindex="0" data-trigger="focus" style="cursor: pointer;" role="button" title="All compilation options")
-              span.btn.btn-sm.btn-light.status-icon
+      select.compiler-picker
+      button.btn.btn-sm.btn-light.input-group-text.picker-popout-button(data-trigger="click" style="cursor: pointer;" role="button" title="Compiler picker popout")
+        span
+          i.fa-solid.fa-arrow-up-right-from-square
+      button.btn.btn-sm.btn-light.input-group-text.prepend-options(tabindex="0" data-trigger="focus" style="cursor: pointer;" role="button" title="All compilation options")
+        span.btn.btn-sm.btn-light.status-icon
      input.conformance-options.form-control(type="text" placeholder="Compiler options..." size="256" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false")
-      .input-group-append
-        button.btn.btn-sm.fas.fa-receipt.d-none.compiler-out.compiler-selector-icon(disabled=true style="cursor: help;" title="This compiler has generated some output. Open its associated pane to read it.")
-        button.btn.btn-sm.fas.fa-times.close.compiler-selector-icon(aria-label="Close" title="Close")
-        button.btn.btn-sm.fas.fa-share.close.extract-compiler.compiler-selector-icon(aria-label="Pop compiler" title="Show compiler")
-        button.btn.btn-sm.fas.fa-copy.close.copy-compiler.compiler-selector-icon(aria-label="Copy compiler" title="Copy compiler")
+      button.btn.btn-sm.fas.fa-receipt.d-none.compiler-out.compiler-selector-icon(disabled=true style="cursor: help;" title="This compiler has generated some output. Open its associated pane to read it.")
+      button.btn.btn-sm.fas.fa-times.close-compiler.compiler-selector-icon(aria-label="Close" title="Close")
+      button.btn.btn-sm.fas.fa-share.extract-compiler.compiler-selector-icon(aria-label="Pop compiler" title="Show compiler")
+      button.btn.btn-sm.fas.fa-copy.copy-compiler.compiler-selector-icon(aria-label="Copy compiler" title="Copy compiler")
--- a/views/templates/widgets/lib-search-result-tpl.pug
+++ b/views/templates/widgets/lib-search-result-tpl.pug
@@ -4,7 +4,7 @@
      span
        b.lib-name &nbsp;
      span.lib-version
-        select.custom-select.custom-select-sm.lib-version-select
+        select.form-select.form-select-sm.lib-version-select
          option -
    .card-body
      p.lib-description &nbsp;
--- a/views/templates/widgets/libs-entry.pug
+++ b/views/templates/widgets/libs-entry.pug
@@ -1,5 +1,4 @@
 #libs-entry
  .input-group.input-group-sm
-    .input-group-prepend
-      label.input-group-text
-    select.custom-select.custom-select-sm
+    label.input-group-text
+    select.form-select.form-select-sm
--- a/views/templates/widgets/possible-override-tpl.pug
+++ b/views/templates/widgets/possible-override-tpl.pug
@@ -3,7 +3,7 @@
    .card-header
      span.override-name
      span.override
-        select.custom-select.custom-select-sm
+        select.form-select.form-select-sm
    .card-body
      p.override-description
      span.override-fav
--- a/views/templates/widgets/possible-runtime-tool-tpl.pug
+++ b/views/templates/widgets/possible-runtime-tool-tpl.pug
@@ -13,4 +13,4 @@
  .runtime-tool-option
    span.tool-option-name
    span.tool-option-select
-      select.tool-option-select.custom-select-sm
+      select.tool-option-select.form-select-sm
--- a/views/templates/widgets/tree-editor-tpl.pug
+++ b/views/templates/widgets/tree-editor-tpl.pug
@@ -1,5 +1,5 @@
 #tree-editor-tpl
-  li.list-group-item.tree-editor-file.input-group-append
+  li.list-group-item.tree-editor-file
    span.filename someresource.txt
    button.btn.delete-file.fa.fa-trash(title="Remove this file" aria-label="Delete")
    button.btn.rename-file.fa.fa-tag(title="Rename this file" aria-label="Rename")