accessibility

# Accessibility Patterns Reference for web accessibility (WCAG 2.2 AA compliance), keyboard navigation, screen reader support, and inclusive design. Sources in `references/sources.md`. ## Iron Law > **EVERY INTERACTION MUST BE POSSIBLE WITHOUT A MOUSE** [1][3] > > Mouse-only interactions exclude users with motor disabilities, power users, and AT users. > Tab order, focus management, and keyboard shortcuts are not optional enhancements. > — WCAG 2.1 Principle 2 (Operable) [1] **Activates for**: interactive UI components · forms · React/JSX or CSS · focus/ARIA/contrast reviews --- ## Keyboard Navigation [1][3] **Focus management**: On modal open, move focus to the first focusable element; on close, return to the trigger. Trap focus inside. [3] ```tsx // CORRECT: Focus trap — APG dialog pattern [3] function Modal({ isOpen, onClose, children }) { const first = useRef<HTMLButtonElement>(null); useEffect(() => { if (isOpen) first.current?.focus(); }, [isOpen]); return ( <div role="dialog" aria-modal="true" onKeyDown={(e) => { if (e.key === 'Escape') onClose(); }}> <button ref={first}>First action</button>{children} </div> ); } ``` **Skip links**: First focusable element — visible on focus, links to `#main-content`. [1][4] **Roving tabIndex**: Active item `tabIndex={0}`, others `tabIndex={-1}` — radio groups, toolbars, tabs. [3] --- ## ARIA and Semantic HTML [2][15][18] **First rule of ARIA**: Use native HTML before adding ARIA roles — no ARIA...