# Accessibility Requirements

> Detailed, enforceable accessibility rules. Every component, page,
> and flow must pass these. Failure is disqualifying — see
> `first-principles.md` P2.

## Perceivable

- [ ] Every image has `alt` text or is marked `alt=""` if decorative.
- [ ] Every video has captions. Every audio has transcripts.
- [ ] Color contrast meets WCAG 2.1 AA (4.5:1 text, 3:1 UI).
- [ ] Information is not conveyed by color alone.
- [ ] Text resizes to 200% without loss of content or function.

## Operable

- [ ] Every interactive element is keyboard-reachable.
- [ ] Focus order is logical and matches visual order.
- [ ] Focus is always visible (≥ 3:1 contrast).
- [ ] No keyboard traps.
- [ ] Touch targets are ≥ 44×44 CSS pixels.
- [ ] Motion can be disabled via `prefers-reduced-motion`.
- [ ] No flashing content > 3 flashes per second.

## Understandable

- [ ] Page language is declared.
- [ ] Form fields have associated labels.
- [ ] Error messages identify the field and the problem.
- [ ] Navigation is consistent across pages.
- [ ] Abbreviations and jargon are explained on first use.

## Robust

- [ ] HTML validates.
- [ ] ARIA is used correctly (roles, states, properties).
- [ ] Components work across assistive technologies.
- [ ] No ARIA is used where native HTML would suffice.

## Testing

Every accessibility requirement is verified by:

1. Automated tool (axe-core, Lighthouse, etc.)
2. Keyboard-only navigation
3. Screen reader (NVDA, VoiceOver) walkthrough
4. Zoom to 200%
5. Reduced motion enabled

All five must pass. Automated-only is not acceptance.