refactor(a11y): comprehensive WCAG 2.2 AA accessibility improvements (#924)

* refactor(a11y): comprehensive WCAG 2.2 AA accessibility improvements

Add skip-to-content link, landmark regions, ARIA attributes, keyboard
navigation, focus styles, reduced-motion support, and i18n keys across
all layouts, partials, shortcodes, and JS components.

- Add skip nav link in baseof.html and id="content" on all <main> tags
- Fix 404 page lang/dir attributes and add <main> landmark
- Add aria-label to banner close, PDF iframe, search input/results
- Remove aria-hidden from back-to-top button
- Add aria-hidden to decorative external link icon
- Add role="tablist" to tabs, aria-expanded to filetree/dropdowns
- Wrap mermaid diagrams in role="img", asciinema in role="region"
- Change theme toggle <p> items to <button role="menuitem"> with
  full keyboard navigation (Arrow/Home/End/Escape)
- Add arrow-key keyboard navigation to tabs component
- Separate sidebar collapsible button from link for independent
  keyboard access with aria-expanded sync
- Sync aria-expanded on all dropdown toggles (theme, lang, navbar,
  hamburger, page context menu)
- Add aria-live search status announcements
- Add 13 new i18n keys, replace hardcoded aria-label strings
- Add prefers-reduced-motion CSS override and focus-visible base styles
- Add aria-label swap on code copy ("Copied!" feedback for AT)
- Add aria-current to active TOC links
- Wrap filetree in <ul> container for proper list semantics
- Add unique aria-label to blog "Read more" links
- Document accessibility guidelines in AGENTS.md

* feat(a11y): enhance focus styles and accessibility for various components

- Add focus-visible styles to badges, buttons, and links for improved keyboard navigation.
- Update breadcrumb, sidebar, and TOC components to include focus-visible outlines.
- Introduce new classes for focus states in the badge and tabs shortcodes.
- Ensure consistent focus styles across all interactive elements to meet WCAG 2.2 AA standards.

* feat(a11y): implement new focus-visible utilities and enhance accessibility styles

- Introduce new utility classes for focus-visible states to improve keyboard navigation.
- Update various components including badges, buttons, and search inputs to utilize new focus-visible styles.
- Refactor existing focus styles to ensure consistency and compliance with accessibility standards.
- Enhance breadcrumb, sidebar, and TOC components with updated focus-visible classes for better user experience.

* chore: add .gitattributes to collapse generated files in PR diffs

* fix: enhance accessibility and improve documentation

- Added alt attributes to images in multiple language documentation files for better accessibility.
- Updated the navbar title partial to remove unnecessary title attribute.
- Improved search input accessibility by adding autocomplete="off".
- Enhanced search partials in both navbar and sidebar with location context.
- Updated SVG icons in various components to include aria-hidden and focusable attributes for improved accessibility compliance.

* fix: improve giscus theme toggle functionality

- Updated the theme toggle options selector to use a data attribute for better specificity.
- Modified the event listener to use a setTimeout for the theme update, ensuring smoother transitions when the theme switcher is clicked.

* fix: resolve axe-core WCAG AA violations across docs pages

Add aria-labels to Hugo task list checkboxes, fix asciinema player
timer accessible names, make Jupyter output cells keyboard-focusable,
and add missing heading hierarchy in shortcodes docs for fa/ja/zh-cn.

* feat: integrate accessibility testing with Playwright and enhance CI workflow

- Added Playwright configuration for accessibility testing.
- Implemented accessibility tests using axe-core for all English pages.
- Created a GitHub Actions workflow to automate accessibility tests on pull requests.
- Updated package dependencies to include @axe-core/playwright and @playwright/test.
- Enhanced sidebar component with data attributes for improved accessibility styling.

* fix: update base URL and improve accessibility labels across multiple languages

- Changed the base URL in Playwright configuration and CI workflow from localhost:3000 to localhost:1313.
- Added accessibility labels for screen readers in various language files, enhancing user experience for visually impaired users.
- Updated the Asciinema script to dynamically set the playback time label for better accessibility compliance.

* refactor: reorganize accessibility tests and update test directory structure

- Moved accessibility tests from the e2e directory to a new tests directory for better organization.
- Updated the test directory path in Playwright configuration.
- Refactored the accessibility test implementation to improve code clarity and maintainability.

* chore: update .gitignore to include Playwright test output directories

- Added entries for 'playwright-report/' and 'test-results/' to the .gitignore file to prevent cluttering the repository with test artifacts.

* refactor: enhance accessibility and improve focus styles across components

- Removed unused utility for focus visibility in CSS and consolidated focus-visible styles for better maintainability.
- Updated various components to use `role` attributes for improved accessibility, including menu items and buttons.
- Enhanced theme toggle and language switch components with appropriate ARIA roles and attributes for better screen reader support.
- Improved the handling of focus states in the navigation and context menus to ensure a consistent user experience.

* chore: update dependencies and enhance accessibility features

- Updated the 'serve' package version in package.json and package-lock.json for improved performance.
- Removed unused 'xml2js' dependency to streamline the project.
- Enhanced the Playwright configuration to better manage the web server setup for testing.
- Improved accessibility in the language switcher and navigation menu by refining focus management and keyboard interactions.
- Updated the back-to-top button to manage tabindex for better accessibility compliance.

* feat: enhance mobile menu accessibility and keyboard interactions

- Added ARIA attributes to manage visibility of the sidebar on mobile devices.
- Implemented focus management for the sidebar when the menu is toggled.
- Introduced keyboard support to close the menu with the Escape key.
- Improved overall accessibility for the hamburger menu and sidebar interactions.

* fix: refine mobile menu keyboard interaction and enhance navbar accessibility

- Updated the Escape key functionality to close the menu only on mobile devices.
- Added a new ARIA attribute to the hamburger menu button for improved accessibility.

Author: imfing

.gitattributes

@@ -0,0 +1,3 @@
+# Mark generated files so they are collapsed by default in GitHub diffs
+assets/css/compiled/main.css linguist-generated=true
+docs/hugo_stats.json linguist-generated=true

.github/workflows/accessibility.yml

@@ -0,0 +1,62 @@
+name: Accessibility Tests
+
+on:
+  pull_request:
+    branches: [main]
+
+concurrency:
+  group: accessibility-${{ github.head_ref || github.ref_name }}
+  cancel-in-progress: true
+
+defaults:
+  run:
+    shell: bash
+
+jobs:
+  a11y:
+    runs-on: ubuntu-latest
+    environment: accessibility
+    env:
+      HUGO_VERSION: 0.147.7
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          submodules: recursive
+
+      - name: Setup Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: "1.24"
+
+      - name: Setup Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: "22"
+          cache: npm
+
+      - name: Setup Hugo
+        run: |
+          wget -O ${{ runner.temp }}/hugo.deb https://github.com/gohugoio/hugo/releases/download/v${HUGO_VERSION}/hugo_extended_${HUGO_VERSION}_linux-amd64.deb \
+          && sudo dpkg -i ${{ runner.temp }}/hugo.deb
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Install Playwright Chromium
+        run: npx playwright install chromium
+
+      - name: Build site
+        run: npm run build
+
+      - name: Run accessibility tests
+        run: npm run test:a11y
+
+      - name: Upload report
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: accessibility-report
+          path: playwright-report/
+          retention-days: 14

.gitignore

@@ -3,3 +3,7 @@ public/
 resources/
 
 .hugo_build.lock
+
+# Playwright
+playwright-report/
+test-results/

AGENTS.md

@@ -94,6 +94,28 @@ The `docs/` directory serves as both documentation and testing ground:
 - Chroma syntax highlighting themes in `assets/css/chroma/`
 - CSS compilation requires Node.js dependencies (PostCSS, Tailwind CSS v4+)
 
+#### Rebuilding CSS after template changes
+
+Tailwind CSS relies on `docs/hugo_stats.json` to know which HTML tags, classes, and IDs are actually used in the built site, so it can tree-shake unused styles. When you modify layouts, partials, or shortcodes you must **regenerate `hugo_stats.json` first**, then rebuild the CSS:
+
+1. **Generate `docs/hugo_stats.json`** — Run Hugo with the `dev.toml` config (which sets `build.buildStats.enable = true`):
+
+   ```bash
+   # Using npm (starts a dev server that writes hugo_stats.json on every rebuild):
+   npm run dev:theme
+
+   # Or a one-shot build using the raw Hugo command:
+   hugo --config=hugo.yaml,../dev.toml --themesDir=../.. --source=docs
+   ```
+
+2. **Build the CSS** — With an up-to-date `hugo_stats.json` in place, compile the stylesheet:
+
+   ```bash
+   npm run build:css
+   ```
+
+> **Why two steps?** `dev.toml` mounts `docs/hugo_stats.json` into the Hugo asset pipeline (`assets/notwatching/hugo_stats.json`) and configures a cache-buster so that changes to the stats file trigger a CSS recompile during `dev:theme`. When running outside the dev server you need to perform these steps manually in order.
+
 ### Customization Points
 
 - Custom partials: `layouts/_partials/custom/`
@@ -147,6 +169,22 @@ The `docs/` directory serves as both documentation and testing ground:
 - Compiled output goes to `assets/css/compiled/main.css`
 - Prettier formatting for Go templates and code consistency
 
+### Accessibility (WCAG Compliance)
+
+All new features and UI changes must follow the [Web Content Accessibility Guidelines (WCAG) 2.2](https://www.w3.org/TR/WCAG22/) at the **AA** conformance level. Key requirements:
+
+- **Semantic HTML**: Use appropriate elements (`<nav>`, `<main>`, `<aside>`, `<button>`, `<ul>`, etc.) instead of generic `<div>`/`<span>` where applicable.
+- **ARIA attributes**: Add `aria-label`, `aria-expanded`, `aria-controls`, `aria-current`, `role`, and other ARIA attributes to interactive components (menus, toggles, dropdowns, modals) so screen readers can interpret them.
+- **Keyboard navigation**: All interactive elements must be reachable and operable via keyboard (`Tab`, `Enter`, `Escape`, arrow keys). Manage focus appropriately when opening/closing menus, modals, and drawers.
+- **Focus indicators**: Never remove visible focus outlines. Use the existing `hextra-focus` utility or equivalent visible focus ring styles.
+- **Color contrast**: Text and interactive elements must meet WCAG AA contrast ratios (4.5:1 for normal text, 3:1 for large text). Verify in both light and dark modes.
+- **Images and icons**: Decorative SVGs/icons should have `aria-hidden="true"`. Meaningful images need descriptive `alt` text.
+- **Skip links and landmarks**: Preserve existing skip-navigation links and ARIA landmark roles (`role="navigation"`, `role="search"`, etc.).
+- **Live regions**: Use `aria-live` for dynamic content updates (e.g., search results, status messages) so assistive technology announces changes.
+- **Form controls**: Associate `<label>` elements with inputs. Provide accessible names for buttons that contain only icons.
+
+When introducing a new component or modifying an existing one, verify it works with keyboard-only navigation and review the rendered HTML for proper semantics and ARIA usage.
+
 ### Testing & Quality Assurance
 
 - Test all changes in `docs/` before releasing

assets/css/compiled/main.css

@@ -1,7 +1,3 @@
 .hextra-archive-timeline {
-  border-left: 2px solid rgba(0, 0, 0, 0.15);
-}
-
-.dark .hextra-archive-timeline {
-  border-left-color: rgba(255, 255, 255, 0.15);
+  @apply hx:border-l-2 hx:border-black/15 hx:dark:border-white/15;
 }

assets/css/components/archives.css

@@ -1,3 +1,3 @@
 .hextra-badge {
   @apply hx:inline-flex hx:items-center;
-}
+}

assets/css/components/badge.css

@@ -2,7 +2,7 @@
   li {
     @apply hx:mx-2.5 hx:wrap-break-word hx:rounded-md hx:contrast-more:border hx:text-gray-800 hx:contrast-more:border-transparent hx:dark:text-gray-300;
     a {
-      @apply hx:focus-visible:outline-none hx:focus:outline-none hx:block hx:scroll-m-12 hx:px-2.5 hx:py-2;
+      @apply hx:focus-visible:outline-none hx:block hx:scroll-m-12 hx:px-2.5 hx:py-2;
     }
 
     .hextra-search-title {

assets/css/components/search.css

@@ -9,13 +9,13 @@
 }
 
 .hextra-sidebar-container {
-  li > div {
+  li > .hextra-sidebar-children {
     @apply hx:h-0;
   }
-  li.open > div {
+  li.open > .hextra-sidebar-children {
     @apply hx:h-auto hx:pt-1;
   }
-  li.open > a > span > svg > path {
+  li.open > .hextra-sidebar-item > .hextra-sidebar-collapsible-button > svg > path {
     @apply hx:rotate-90;
   }
 }

assets/css/components/sidebar.css

@@ -43,12 +43,37 @@ body {
   @apply hx:outline-none hx:ring-2 hx:ring-primary-200 hx:ring-offset-1 hx:ring-offset-primary-300 hx:dark:ring-primary-800 hx:dark:ring-offset-primary-700;
 }
 
+@utility hextra-focus-visible {
+  @apply hx:focus-visible:outline-none hx:focus-visible:ring-2 hx:focus-visible:ring-primary-200 hx:focus-visible:ring-offset-1 hx:focus-visible:ring-offset-primary-300 hx:dark:focus-visible:ring-primary-800 hx:dark:focus-visible:ring-offset-primary-700;
+}
+
+@utility hextra-focus-visible-inset {
+  @apply hx:focus-visible:outline-none hx:focus-visible:ring-inset hx:focus-visible:ring-2 hx:focus-visible:ring-primary-200 hx:dark:focus-visible:ring-primary-800 hx:focus-visible:ring-offset-0;
+}
+
 @layer base {
   abbr:where([title]) {
     cursor: help;
   }
 }
 
+@media (prefers-reduced-motion: reduce) {
+  *, *::before, *::after {
+    animation-duration: 0.01ms !important;
+    animation-iteration-count: 1 !important;
+    transition-duration: 0.01ms !important;
+    scroll-behavior: auto !important;
+  }
+}
+
+@layer base {
+  :where(a, button, [role="tab"], [role="menuitem"], [role="menuitemradio"], input, select, textarea, [tabindex="0"]):not(
+      [class*="hextra-focus-visible"]
+    ):focus-visible {
+    @apply hx:hextra-focus;
+  }
+}
+
 @import "./typography.css";
 @import "./highlight.css";
 @import "./components/cards.css";