accessibility-implementation

Technical implementation of WCAG guidelines, ARIA patterns, and assistive technology support.

When to Use This Skill

| Use this skill when... | Use design-tokens instead when... | |---|---| | Implementing WCAG 2.1/2.2 success criteria in code | Setting up CSS custom properties or theme systems | | Adding ARIA roles, states, or live regions | Defining semantic colour tokens used by themes | | Wiring keyboard navigation, focus traps, or skip links | Organizing primitive/semantic/component token tiers | | Auditing components with axe-core, jest-axe, or Playwright | Implementing light/dark mode token overrides |

Core Expertise

• WCAG Compliance: Implementing WCAG 2.1/2.2 success criteria in code
• ARIA Patterns: Correct usage of roles, states, and properties
• Keyboard Navigation: Focus management, key handlers, logical tab order
• Screen Readers: Content structure, announcements, live regions
• Testing: Automated and manual accessibility testing

WCAG Quick Reference

Level A (Must Have)

| Criterion | Implementation | |-----------|----------------| | 1.1.1 Non-text Content | alt for images, labels for inputs | | 1.3.1 Info and Relationships | Semantic HTML, ARIA relationships | | 2.1.1 Keyboard | All interactive elements keyboard accessible | | 2.4.1 Bypass Blocks | Skip links, landmarks | | 4.1.2 Name, Role, Value | ARIA labels, roles for custom widgets |

Level AA (Should Have)

| Criterion | Implementation | |-----------|----------------| | 1.4.3 Contrast (Minimum) | 4.5:1 text, 3:1 large text | | 1.4.11 Non-text Contrast | 3:1 for UI components | | 2.4.6 Headings and Labels | Descriptive, hierarchical headings | | 2.4.7 Focus Visible | Visible focus indicator (2px+ outline) |

Best Practices

Semantic HTML First

Use native HTML elements before ARIA. A <button> is better than <div role="button">.

Don't Override Default Behavior

Native elements have built-in accessibility. Don't break it with JavaScript.

Test with Real Users

Automated tools catch ~30% of issues. Manual testing with assistive technology is essential.

Provide Multiple Ways

Offer keyboard, mouse, and touch alternatives for all interactions.

References

• WCAG 2.1 Guidelines: https://www.w3.org/WAI/WCAG21/quickref/
• ARIA Authoring Practices: https://www.w3.org/WAI/ARIA/apg/
• axe-core Rules: https://dequeuniversity.com/rules/axe/
• A11y Project Checklist: https://www.a11yproject.com/checklist/

For full ARIA widget patterns, keyboard navigation implementations, testing recipes, common fixes, and CSS utilities, see REFERENCE.md.