Add 260+ Claude Code skills from skills.sh
Complete collection of AI agent skills including: - Frontend Development (Vue, React, Next.js, Three.js) - Backend Development (NestJS, FastAPI, Node.js) - Mobile Development (React Native, Expo) - Testing (E2E, frontend, webapp) - DevOps (GitHub Actions, CI/CD) - Marketing (SEO, copywriting, analytics) - Security (binary analysis, vulnerability scanning) - And many more... Synchronized from: https://skills.sh/ Co-Authored-By: Claude <noreply@anthropic.com>
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accessibility/skill.md
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accessibility/skill.md
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---
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name: accessibility
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description: |
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Build WCAG 2.1 AA compliant websites with semantic HTML, proper ARIA, focus management, and screen reader support. Includes color contrast (4.5:1 text), keyboard navigation, form labels, and live regions.
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Use when implementing accessible interfaces, fixing screen reader issues, keyboard navigation, or troubleshooting "focus outline missing", "aria-label required", "insufficient contrast".
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---
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# Web Accessibility (WCAG 2.1 AA)
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**Status**: Production Ready ✅
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**Last Updated**: 2026-01-14
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**Dependencies**: None (framework-agnostic)
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**Standards**: WCAG 2.1 Level AA
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---
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## Quick Start (5 Minutes)
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### 1. Semantic HTML Foundation
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Choose the right element - don't use `div` for everything:
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```html
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<!-- ❌ WRONG - divs with onClick -->
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<div onclick="submit()">Submit</div>
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<div onclick="navigate()">Next page</div>
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<!-- ✅ CORRECT - semantic elements -->
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<button type="submit">Submit</button>
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<a href="/next">Next page</a>
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```
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**Why this matters:**
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- Semantic elements have built-in keyboard support
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- Screen readers announce role automatically
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- Browser provides default accessible behaviors
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### 2. Focus Management
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Make interactive elements keyboard-accessible:
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```css
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/* ❌ WRONG - removes focus outline */
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button:focus { outline: none; }
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/* ✅ CORRECT - custom accessible outline */
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button:focus-visible {
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outline: 2px solid var(--primary);
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outline-offset: 2px;
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}
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```
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**CRITICAL:**
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- Never remove focus outlines without replacement
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- Use `:focus-visible` to show only on keyboard focus
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- Ensure 3:1 contrast ratio for focus indicators
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### 3. Text Alternatives
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Every non-text element needs a text alternative:
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```html
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<!-- ❌ WRONG - no alt text -->
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<img src="logo.png">
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<button><svg>...</svg></button>
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<!-- ✅ CORRECT - proper alternatives -->
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<img src="logo.png" alt="Company Name">
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<button aria-label="Close dialog"><svg>...</svg></button>
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```
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---
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## The 5-Step Accessibility Process
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### Step 1: Choose Semantic HTML
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**Decision tree for element selection:**
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```
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Need clickable element?
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├─ Navigates to another page? → <a href="...">
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├─ Submits form? → <button type="submit">
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├─ Opens dialog? → <button aria-haspopup="dialog">
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└─ Other action? → <button type="button">
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Grouping content?
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├─ Self-contained article? → <article>
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├─ Thematic section? → <section>
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├─ Navigation links? → <nav>
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└─ Supplementary info? → <aside>
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Form element?
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├─ Text input? → <input type="text">
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├─ Multiple choice? → <select> or <input type="radio">
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├─ Toggle? → <input type="checkbox"> or <button aria-pressed>
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└─ Long text? → <textarea>
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```
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**See `references/semantic-html.md` for complete guide.**
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### Step 2: Add ARIA When Needed
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**Golden rule: Use ARIA only when HTML can't express the pattern.**
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```html
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<!-- ❌ WRONG - unnecessary ARIA -->
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<button role="button">Click me</button> <!-- Button already has role -->
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<!-- ✅ CORRECT - ARIA fills semantic gap -->
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<div role="dialog" aria-labelledby="title" aria-modal="true">
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<h2 id="title">Confirm action</h2>
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<!-- No HTML dialog yet, so role needed -->
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</div>
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<!-- ✅ BETTER - Use native HTML when available -->
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<dialog aria-labelledby="title">
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<h2 id="title">Confirm action</h2>
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</dialog>
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```
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**Common ARIA patterns:**
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- `aria-label` - When visible label doesn't exist
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- `aria-labelledby` - Reference existing text as label
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- `aria-describedby` - Additional description
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- `aria-live` - Announce dynamic updates
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- `aria-expanded` - Collapsible/expandable state
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**See `references/aria-patterns.md` for complete patterns.**
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### Step 3: Implement Keyboard Navigation
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**All interactive elements must be keyboard-accessible:**
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```typescript
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// Tab order management
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function Dialog({ onClose }) {
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const dialogRef = useRef<HTMLDivElement>(null);
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const previousFocus = useRef<HTMLElement | null>(null);
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useEffect(() => {
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// Save previous focus
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previousFocus.current = document.activeElement as HTMLElement;
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// Focus first element in dialog
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const firstFocusable = dialogRef.current?.querySelector('button, [href], input, select, textarea, [tabindex]:not([tabindex="-1"])');
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(firstFocusable as HTMLElement)?.focus();
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// Trap focus within dialog
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const handleKeyDown = (e: KeyboardEvent) => {
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if (e.key === 'Escape') onClose();
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if (e.key === 'Tab') {
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// Focus trap logic here
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}
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};
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document.addEventListener('keydown', handleKeyDown);
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return () => {
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document.removeEventListener('keydown', handleKeyDown);
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// Restore focus on close
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previousFocus.current?.focus();
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};
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}, [onClose]);
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return <div ref={dialogRef} role="dialog">...</div>;
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}
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```
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**Essential keyboard patterns:**
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- Tab/Shift+Tab: Navigate between focusable elements
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- Enter/Space: Activate buttons/links
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- Arrow keys: Navigate within components (tabs, menus)
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- Escape: Close dialogs/menus
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- Home/End: Jump to first/last item
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**See `references/focus-management.md` for complete patterns.**
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### Step 4: Ensure Color Contrast
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**WCAG AA requirements:**
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- Normal text (under 18pt): 4.5:1 contrast ratio
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- Large text (18pt+ or 14pt+ bold): 3:1 contrast ratio
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- UI components (buttons, borders): 3:1 contrast ratio
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```css
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/* ❌ WRONG - insufficient contrast */
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:root {
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--background: #ffffff;
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--text: #999999; /* 2.8:1 - fails WCAG AA */
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}
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/* ✅ CORRECT - sufficient contrast */
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:root {
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--background: #ffffff;
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--text: #595959; /* 4.6:1 - passes WCAG AA */
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}
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```
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**Testing tools:**
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- Browser DevTools (Chrome/Firefox have built-in checkers)
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- Contrast checker extensions
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- axe DevTools extension
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**See `references/color-contrast.md` for complete guide.**
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### Step 5: Make Forms Accessible
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**Every form input needs a visible label:**
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```html
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<!-- ❌ WRONG - placeholder is not a label -->
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<input type="email" placeholder="Email address">
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<!-- ✅ CORRECT - proper label -->
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<label for="email">Email address</label>
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<input type="email" id="email" name="email" required aria-required="true">
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```
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**Error handling:**
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```html
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<label for="email">Email address</label>
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<input
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type="email"
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id="email"
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name="email"
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aria-invalid="true"
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aria-describedby="email-error"
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>
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<span id="email-error" role="alert">
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Please enter a valid email address
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</span>
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```
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**Live regions for dynamic errors:**
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```html
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<div role="alert" aria-live="assertive" aria-atomic="true">
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Form submission failed. Please fix the errors above.
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</div>
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```
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**See `references/forms-validation.md` for complete patterns.**
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---
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## Critical Rules
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### Always Do
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✅ Use semantic HTML elements first (button, a, nav, article, etc.)
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✅ Provide text alternatives for all non-text content
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✅ Ensure 4.5:1 contrast for normal text, 3:1 for large text/UI
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✅ Make all functionality keyboard accessible
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✅ Test with keyboard only (unplug mouse)
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✅ Test with screen reader (NVDA on Windows, VoiceOver on Mac)
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✅ Use proper heading hierarchy (h1 → h2 → h3, no skipping)
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✅ Label all form inputs with visible labels
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✅ Provide focus indicators (never just `outline: none`)
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✅ Use `aria-live` for dynamic content updates
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### Never Do
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❌ Use `div` with `onClick` instead of `button`
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❌ Remove focus outlines without replacement
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❌ Use color alone to convey information
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❌ Use placeholders as labels
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❌ Skip heading levels (h1 → h3)
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❌ Use `tabindex` > 0 (messes with natural order)
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❌ Add ARIA when semantic HTML exists
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❌ Forget to restore focus after closing dialogs
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❌ Use `role="presentation"` on focusable elements
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❌ Create keyboard traps (no way to escape)
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---
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## Known Issues Prevention
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This skill prevents **12** documented accessibility issues:
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### Issue #1: Missing Focus Indicators
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**Error**: Interactive elements have no visible focus indicator
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**Source**: WCAG 2.4.7 (Focus Visible)
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**Why It Happens**: CSS reset removes default outline
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**Prevention**: Always provide custom focus-visible styles
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### Issue #2: Insufficient Color Contrast
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**Error**: Text has less than 4.5:1 contrast ratio
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**Source**: WCAG 1.4.3 (Contrast Minimum)
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**Why It Happens**: Using light gray text on white background
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**Prevention**: Test all text colors with contrast checker
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### Issue #3: Missing Alt Text
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**Error**: Images missing alt attributes
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**Source**: WCAG 1.1.1 (Non-text Content)
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**Why It Happens**: Forgot to add or thought it was optional
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**Prevention**: Add alt="" for decorative, descriptive alt for meaningful images
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### Issue #4: Keyboard Navigation Broken
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**Error**: Interactive elements not reachable by keyboard
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**Source**: WCAG 2.1.1 (Keyboard)
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**Why It Happens**: Using div onClick instead of button
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**Prevention**: Use semantic interactive elements (button, a)
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### Issue #5: Form Inputs Without Labels
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**Error**: Input fields missing associated labels
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**Source**: WCAG 3.3.2 (Labels or Instructions)
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**Why It Happens**: Using placeholder as label
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**Prevention**: Always use `<label>` element with for/id association
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### Issue #6: Skipped Heading Levels
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**Error**: Heading hierarchy jumps from h1 to h3
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**Source**: WCAG 1.3.1 (Info and Relationships)
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**Why It Happens**: Using headings for visual styling instead of semantics
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**Prevention**: Use headings in order, style with CSS
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### Issue #7: No Focus Trap in Dialogs
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**Error**: Tab key exits dialog to background content
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**Source**: WCAG 2.4.3 (Focus Order)
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**Why It Happens**: No focus trap implementation
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**Prevention**: Implement focus trap for modal dialogs
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### Issue #8: Missing aria-live for Dynamic Content
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**Error**: Screen reader doesn't announce updates
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**Source**: WCAG 4.1.3 (Status Messages)
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**Why It Happens**: Dynamic content added without announcement
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**Prevention**: Use aria-live="polite" or "assertive"
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### Issue #9: Color-Only Information
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**Error**: Using only color to convey status
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**Source**: WCAG 1.4.1 (Use of Color)
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**Why It Happens**: Red text for errors without icon/text
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**Prevention**: Add icon + text label, not just color
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### Issue #10: Non-descriptive Link Text
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**Error**: Links with "click here" or "read more"
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**Source**: WCAG 2.4.4 (Link Purpose)
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**Why It Happens**: Generic link text without context
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**Prevention**: Use descriptive link text or aria-label
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### Issue #11: Auto-playing Media
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**Error**: Video/audio auto-plays without user control
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**Source**: WCAG 1.4.2 (Audio Control)
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**Why It Happens**: Autoplay attribute without controls
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**Prevention**: Require user interaction to start media
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### Issue #12: Inaccessible Custom Controls
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**Error**: Custom select/checkbox without keyboard support
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**Source**: WCAG 4.1.2 (Name, Role, Value)
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**Why It Happens**: Building from divs without ARIA
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**Prevention**: Use native elements or implement full ARIA pattern
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---
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## WCAG 2.1 AA Quick Checklist
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### Perceivable
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- [ ] All images have alt text (or alt="" if decorative)
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- [ ] Text contrast ≥ 4.5:1 (normal), ≥ 3:1 (large)
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- [ ] Color not used alone to convey information
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- [ ] Text can be resized to 200% without loss of content
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- [ ] No auto-playing audio >3 seconds
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### Operable
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- [ ] All functionality keyboard accessible
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- [ ] No keyboard traps
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- [ ] Visible focus indicators
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- [ ] Users can pause/stop/hide moving content
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- [ ] Page titles describe purpose
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- [ ] Focus order is logical
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- [ ] Link purpose clear from text or context
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- [ ] Multiple ways to find pages (menu, search, sitemap)
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- [ ] Headings and labels describe purpose
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### Understandable
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- [ ] Page language specified (`<html lang="en">`)
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- [ ] Language changes marked (`<span lang="es">`)
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- [ ] No unexpected context changes on focus/input
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- [ ] Consistent navigation across site
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- [ ] Form labels/instructions provided
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- [ ] Input errors identified and described
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- [ ] Error prevention for legal/financial/data changes
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### Robust
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- [ ] Valid HTML (no parsing errors)
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- [ ] Name, role, value available for all UI components
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- [ ] Status messages identified (aria-live)
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---
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## Testing Workflow
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### 1. Keyboard-Only Testing (5 minutes)
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```
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1. Unplug mouse or hide cursor
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2. Tab through entire page
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- Can you reach all interactive elements?
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- Can you activate all buttons/links?
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- Is focus order logical?
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3. Use Enter/Space to activate
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4. Use Escape to close dialogs
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5. Use arrow keys in menus/tabs
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```
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### 2. Screen Reader Testing (10 minutes)
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**NVDA (Windows - Free)**:
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- Download: https://www.nvaccess.org/download/
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- Start: Ctrl+Alt+N
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- Navigate: Arrow keys or Tab
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- Read: NVDA+Down arrow
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- Stop: NVDA+Q
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**VoiceOver (Mac - Built-in)**:
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- Start: Cmd+F5
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- Navigate: VO+Right/Left arrow (VO = Ctrl+Option)
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- Read: VO+A (read all)
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- Stop: Cmd+F5
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**What to test:**
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- Are all interactive elements announced?
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- Are images described properly?
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- Are form labels read with inputs?
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- Are dynamic updates announced?
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- Is heading structure clear?
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### 3. Automated Testing
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**axe DevTools** (Browser extension - highly recommended):
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- Install: Chrome/Firefox extension
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- Run: F12 → axe DevTools tab → Scan
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- Fix: Review violations, follow remediation
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- Retest: Scan again after fixes
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**Lighthouse** (Built into Chrome):
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- Open DevTools (F12)
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- Lighthouse tab
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- Select "Accessibility" category
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- Generate report
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- Score 90+ is good, 100 is ideal
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---
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## Common Patterns
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### Pattern 1: Accessible Dialog/Modal
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```typescript
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interface DialogProps {
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isOpen: boolean;
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onClose: () => void;
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title: string;
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children: React.ReactNode;
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}
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function Dialog({ isOpen, onClose, title, children }: DialogProps) {
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const dialogRef = useRef<HTMLDivElement>(null);
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useEffect(() => {
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if (!isOpen) return;
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const previousFocus = document.activeElement as HTMLElement;
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// Focus first focusable element
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const firstFocusable = dialogRef.current?.querySelector(
|
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'button, [href], input, select, textarea, [tabindex]:not([tabindex="-1"])'
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) as HTMLElement;
|
||||
firstFocusable?.focus();
|
||||
|
||||
// Focus trap
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||||
const handleKeyDown = (e: KeyboardEvent) => {
|
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if (e.key === 'Escape') {
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onClose();
|
||||
}
|
||||
if (e.key === 'Tab') {
|
||||
const focusableElements = dialogRef.current?.querySelectorAll(
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'button, [href], input, select, textarea, [tabindex]:not([tabindex="-1"])'
|
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);
|
||||
if (!focusableElements?.length) return;
|
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|
||||
const first = focusableElements[0] as HTMLElement;
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||||
const last = focusableElements[focusableElements.length - 1] as HTMLElement;
|
||||
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||||
if (e.shiftKey && document.activeElement === first) {
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e.preventDefault();
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last.focus();
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} else if (!e.shiftKey && document.activeElement === last) {
|
||||
e.preventDefault();
|
||||
first.focus();
|
||||
}
|
||||
}
|
||||
};
|
||||
|
||||
document.addEventListener('keydown', handleKeyDown);
|
||||
|
||||
return () => {
|
||||
document.removeEventListener('keydown', handleKeyDown);
|
||||
previousFocus?.focus();
|
||||
};
|
||||
}, [isOpen, onClose]);
|
||||
|
||||
if (!isOpen) return null;
|
||||
|
||||
return (
|
||||
<>
|
||||
{/* Backdrop */}
|
||||
<div
|
||||
className="dialog-backdrop"
|
||||
onClick={onClose}
|
||||
aria-hidden="true"
|
||||
/>
|
||||
|
||||
{/* Dialog */}
|
||||
<div
|
||||
ref={dialogRef}
|
||||
role="dialog"
|
||||
aria-modal="true"
|
||||
aria-labelledby="dialog-title"
|
||||
className="dialog"
|
||||
>
|
||||
<h2 id="dialog-title">{title}</h2>
|
||||
<div className="dialog-content">{children}</div>
|
||||
<button onClick={onClose} aria-label="Close dialog">×</button>
|
||||
</div>
|
||||
</>
|
||||
);
|
||||
}
|
||||
```
|
||||
|
||||
**When to use**: Any modal dialog or overlay that blocks interaction with background content.
|
||||
|
||||
### Pattern 2: Accessible Tabs
|
||||
|
||||
```typescript
|
||||
function Tabs({ tabs }: { tabs: Array<{ label: string; content: React.ReactNode }> }) {
|
||||
const [activeIndex, setActiveIndex] = useState(0);
|
||||
|
||||
const handleKeyDown = (e: React.KeyboardEvent, index: number) => {
|
||||
if (e.key === 'ArrowLeft') {
|
||||
e.preventDefault();
|
||||
const newIndex = index === 0 ? tabs.length - 1 : index - 1;
|
||||
setActiveIndex(newIndex);
|
||||
} else if (e.key === 'ArrowRight') {
|
||||
e.preventDefault();
|
||||
const newIndex = index === tabs.length - 1 ? 0 : index + 1;
|
||||
setActiveIndex(newIndex);
|
||||
} else if (e.key === 'Home') {
|
||||
e.preventDefault();
|
||||
setActiveIndex(0);
|
||||
} else if (e.key === 'End') {
|
||||
e.preventDefault();
|
||||
setActiveIndex(tabs.length - 1);
|
||||
}
|
||||
};
|
||||
|
||||
return (
|
||||
<div>
|
||||
<div role="tablist" aria-label="Content tabs">
|
||||
{tabs.map((tab, index) => (
|
||||
<button
|
||||
key={index}
|
||||
role="tab"
|
||||
aria-selected={activeIndex === index}
|
||||
aria-controls={`panel-${index}`}
|
||||
id={`tab-${index}`}
|
||||
tabIndex={activeIndex === index ? 0 : -1}
|
||||
onClick={() => setActiveIndex(index)}
|
||||
onKeyDown={(e) => handleKeyDown(e, index)}
|
||||
>
|
||||
{tab.label}
|
||||
</button>
|
||||
))}
|
||||
</div>
|
||||
{tabs.map((tab, index) => (
|
||||
<div
|
||||
key={index}
|
||||
role="tabpanel"
|
||||
id={`panel-${index}`}
|
||||
aria-labelledby={`tab-${index}`}
|
||||
hidden={activeIndex !== index}
|
||||
tabIndex={0}
|
||||
>
|
||||
{tab.content}
|
||||
</div>
|
||||
))}
|
||||
</div>
|
||||
);
|
||||
}
|
||||
```
|
||||
|
||||
**When to use**: Tabbed interface with multiple panels.
|
||||
|
||||
### Pattern 3: Skip Links
|
||||
|
||||
```html
|
||||
<!-- Place at very top of body -->
|
||||
<a href="#main-content" class="skip-link">
|
||||
Skip to main content
|
||||
</a>
|
||||
|
||||
<style>
|
||||
.skip-link {
|
||||
position: absolute;
|
||||
top: -40px;
|
||||
left: 0;
|
||||
background: var(--primary);
|
||||
color: white;
|
||||
padding: 8px 16px;
|
||||
z-index: 9999;
|
||||
}
|
||||
|
||||
.skip-link:focus {
|
||||
top: 0;
|
||||
}
|
||||
</style>
|
||||
|
||||
<!-- Then in your layout -->
|
||||
<main id="main-content" tabindex="-1">
|
||||
<!-- Page content -->
|
||||
</main>
|
||||
```
|
||||
|
||||
**When to use**: All multi-page websites with navigation/header before main content.
|
||||
|
||||
### Pattern 4: Accessible Form with Validation
|
||||
|
||||
```typescript
|
||||
function ContactForm() {
|
||||
const [errors, setErrors] = useState<Record<string, string>>({});
|
||||
const [touched, setTouched] = useState<Record<string, boolean>>({});
|
||||
|
||||
const validateEmail = (email: string) => {
|
||||
if (!email) return 'Email is required';
|
||||
if (!/^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(email)) return 'Email is invalid';
|
||||
return '';
|
||||
};
|
||||
|
||||
const handleBlur = (field: string, value: string) => {
|
||||
setTouched(prev => ({ ...prev, [field]: true }));
|
||||
const error = validateEmail(value);
|
||||
setErrors(prev => ({ ...prev, [field]: error }));
|
||||
};
|
||||
|
||||
return (
|
||||
<form>
|
||||
<div>
|
||||
<label htmlFor="email">Email address *</label>
|
||||
<input
|
||||
type="email"
|
||||
id="email"
|
||||
name="email"
|
||||
required
|
||||
aria-required="true"
|
||||
aria-invalid={touched.email && !!errors.email}
|
||||
aria-describedby={errors.email ? 'email-error' : undefined}
|
||||
onBlur={(e) => handleBlur('email', e.target.value)}
|
||||
/>
|
||||
{touched.email && errors.email && (
|
||||
<span id="email-error" role="alert" className="error">
|
||||
{errors.email}
|
||||
</span>
|
||||
)}
|
||||
</div>
|
||||
|
||||
<button type="submit">Submit</button>
|
||||
|
||||
{/* Global form error */}
|
||||
<div role="alert" aria-live="assertive" aria-atomic="true">
|
||||
{/* Dynamic error message appears here */}
|
||||
</div>
|
||||
</form>
|
||||
);
|
||||
}
|
||||
```
|
||||
|
||||
**When to use**: All forms with validation.
|
||||
|
||||
---
|
||||
|
||||
## Using Bundled Resources
|
||||
|
||||
### References (references/)
|
||||
|
||||
Detailed documentation for deep dives:
|
||||
|
||||
- **wcag-checklist.md** - Complete WCAG 2.1 Level A & AA requirements with examples
|
||||
- **semantic-html.md** - Element selection guide, when to use which tag
|
||||
- **aria-patterns.md** - ARIA roles, states, properties, and when to use them
|
||||
- **focus-management.md** - Focus order, focus traps, focus restoration patterns
|
||||
- **color-contrast.md** - Contrast requirements, testing tools, color palette tips
|
||||
- **forms-validation.md** - Accessible form patterns, error handling, announcements
|
||||
|
||||
**When Claude should load these**:
|
||||
- User asks for complete WCAG checklist
|
||||
- Deep dive into specific pattern (tabs, accordions, etc.)
|
||||
- Color contrast issues or palette design
|
||||
- Complex form validation scenarios
|
||||
|
||||
### Agents (agents/)
|
||||
|
||||
- **a11y-auditor.md** - Automated accessibility auditor that checks pages for violations
|
||||
|
||||
**When to use**: Request accessibility audit of existing page/component.
|
||||
|
||||
---
|
||||
|
||||
## Advanced Topics
|
||||
|
||||
### ARIA Live Regions
|
||||
|
||||
Three politeness levels:
|
||||
|
||||
```html
|
||||
<!-- Polite: Wait for screen reader to finish current announcement -->
|
||||
<div aria-live="polite">New messages: 3</div>
|
||||
|
||||
<!-- Assertive: Interrupt immediately -->
|
||||
<div aria-live="assertive" role="alert">
|
||||
Error: Form submission failed
|
||||
</div>
|
||||
|
||||
<!-- Off: Don't announce (default) -->
|
||||
<div aria-live="off">Loading...</div>
|
||||
```
|
||||
|
||||
**Best practices:**
|
||||
- Use `polite` for non-critical updates (notifications, counters)
|
||||
- Use `assertive` for errors and critical alerts
|
||||
- Use `aria-atomic="true"` to read entire region on change
|
||||
- Keep messages concise and meaningful
|
||||
|
||||
### Focus Management in SPAs
|
||||
|
||||
React Router doesn't reset focus on navigation - you need to handle it:
|
||||
|
||||
```typescript
|
||||
function App() {
|
||||
const location = useLocation();
|
||||
const mainRef = useRef<HTMLElement>(null);
|
||||
|
||||
useEffect(() => {
|
||||
// Focus main content on route change
|
||||
mainRef.current?.focus();
|
||||
// Announce page title to screen readers
|
||||
const title = document.title;
|
||||
const announcement = document.createElement('div');
|
||||
announcement.setAttribute('role', 'status');
|
||||
announcement.setAttribute('aria-live', 'polite');
|
||||
announcement.textContent = `Navigated to ${title}`;
|
||||
document.body.appendChild(announcement);
|
||||
setTimeout(() => announcement.remove(), 1000);
|
||||
}, [location.pathname]);
|
||||
|
||||
return <main ref={mainRef} tabIndex={-1} id="main-content">...</main>;
|
||||
}
|
||||
```
|
||||
|
||||
### Accessible Data Tables
|
||||
|
||||
```html
|
||||
<table>
|
||||
<caption>Monthly sales by region</caption>
|
||||
<thead>
|
||||
<tr>
|
||||
<th scope="col">Region</th>
|
||||
<th scope="col">Q1</th>
|
||||
<th scope="col">Q2</th>
|
||||
</tr>
|
||||
</thead>
|
||||
<tbody>
|
||||
<tr>
|
||||
<th scope="row">North</th>
|
||||
<td>$10,000</td>
|
||||
<td>$12,000</td>
|
||||
</tr>
|
||||
</tbody>
|
||||
</table>
|
||||
```
|
||||
|
||||
**Key attributes:**
|
||||
- `<caption>` - Describes table purpose
|
||||
- `scope="col"` - Identifies column headers
|
||||
- `scope="row"` - Identifies row headers
|
||||
- Associates data cells with headers for screen readers
|
||||
|
||||
---
|
||||
|
||||
## Official Documentation
|
||||
|
||||
- **WCAG 2.1**: https://www.w3.org/WAI/WCAG21/quickref/
|
||||
- **MDN Accessibility**: https://developer.mozilla.org/en-US/docs/Web/Accessibility
|
||||
- **ARIA Authoring Practices**: https://www.w3.org/WAI/ARIA/apg/
|
||||
- **WebAIM**: https://webaim.org/articles/
|
||||
- **axe DevTools**: https://www.deque.com/axe/devtools/
|
||||
|
||||
---
|
||||
|
||||
## Troubleshooting
|
||||
|
||||
### Problem: Focus indicators not visible
|
||||
|
||||
**Symptoms**: Can tab through page but don't see where focus is
|
||||
**Cause**: CSS removed outlines or insufficient contrast
|
||||
**Solution**:
|
||||
```css
|
||||
*:focus-visible {
|
||||
outline: 2px solid var(--primary);
|
||||
outline-offset: 2px;
|
||||
}
|
||||
```
|
||||
|
||||
### Problem: Screen reader not announcing updates
|
||||
|
||||
**Symptoms**: Dynamic content changes but no announcement
|
||||
**Cause**: No aria-live region
|
||||
**Solution**: Wrap dynamic content in `<div aria-live="polite">` or use role="alert"
|
||||
|
||||
### Problem: Dialog focus escapes to background
|
||||
|
||||
**Symptoms**: Tab key navigates to elements behind dialog
|
||||
**Cause**: No focus trap
|
||||
**Solution**: Implement focus trap (see Pattern 1 above)
|
||||
|
||||
### Problem: Form errors not announced
|
||||
|
||||
**Symptoms**: Visual errors appear but screen reader doesn't notice
|
||||
**Cause**: No aria-invalid or role="alert"
|
||||
**Solution**: Use aria-invalid + aria-describedby pointing to error message with role="alert"
|
||||
|
||||
---
|
||||
|
||||
## Complete Setup Checklist
|
||||
|
||||
Use this for every page/component:
|
||||
|
||||
- [ ] All interactive elements are keyboard accessible
|
||||
- [ ] Visible focus indicators on all focusable elements
|
||||
- [ ] Images have alt text (or alt="" if decorative)
|
||||
- [ ] Text contrast ≥ 4.5:1 (test with axe or Lighthouse)
|
||||
- [ ] Form inputs have associated labels (not just placeholders)
|
||||
- [ ] Heading hierarchy is logical (no skipped levels)
|
||||
- [ ] Page has `<html lang="en">` or appropriate language
|
||||
- [ ] Dialogs have focus trap and restore focus on close
|
||||
- [ ] Dynamic content uses aria-live or role="alert"
|
||||
- [ ] Color not used alone to convey information
|
||||
- [ ] Tested with keyboard only (no mouse)
|
||||
- [ ] Tested with screen reader (NVDA or VoiceOver)
|
||||
- [ ] Ran axe DevTools scan (0 violations)
|
||||
- [ ] Lighthouse accessibility score ≥ 90
|
||||
|
||||
---
|
||||
|
||||
**Questions? Issues?**
|
||||
|
||||
1. Check `references/wcag-checklist.md` for complete requirements
|
||||
2. Use `/a11y-auditor` agent to scan your page
|
||||
3. Run axe DevTools for automated testing
|
||||
4. Test with actual keyboard + screen reader
|
||||
|
||||
---
|
||||
|
||||
**Standards**: WCAG 2.1 Level AA
|
||||
**Testing Tools**: axe DevTools, Lighthouse, NVDA, VoiceOver
|
||||
**Success Criteria**: 90+ Lighthouse score, 0 critical violations
|
||||
Reference in New Issue
Block a user