better-accessibility

Files (8)

• SKILL.md
• openai.yaml · agents/
• focus-and-keyboard.md
• forms.md
• hit-areas.md
• motion-and-zoom.md
• screen-readers.md
• semantics-and-aria.md

SKILL.md (first lines)

# Accessibility

This skill reviews and fixes semantics, keyboard and focus behavior, accessible names, forms, announcements, motion and zoom. It reports each failure against the WCAG criterion it breaks and writes the fix in the project's styling system.

Reviewing means two walks. Keyboard-only, where every flow completes without a mouse. Then screen-reader, where every control announces a name, a role and its state. When unsure, take the platform default over a custom rebuild, and remove ARIA rather than add it.

Contrast measurement and color fixes belong to `better-colors`. Text sizing, iOS input zoom and language metadata belong to `better-typography`. Spacing between targets and spatial RTL belong to `better-layout`. Label, error and alt-text wording belong to `better-writing`. Animation recipes, hover styling and scroll containment belong to `better-ui`.

## Criteria, not conventions

A finding cites a WCAG 2.2 Level A or AA criterion by number, or a concrete task an assistive-technology user cannot complete. Everything else is a recommendation and never `HIGH`. That covers AAA criteria, APG conventions, the one-`<h1>` and no-skipped-levels outline and the 44px and 40px targets. The criterion thresholds below are exact. The larger targets are heuristics, so keep an established, usable density.

## Native elements first

The first rule of ARIA: don't use ARIA when a native element exists. `<button>` for actions, `<a href>` for navigation, never `<div onClick>`. A real link must support Cmd/Ctrl/middle-click. See [semantics-and-aria.md](semantics-and-aria.md) for landmarks and button-vs-link.

## Disabled means unavailable

Use native `disabled` when a control is genuinely unavailable. Reach for `aria-disabled="true"` only when it should stay focusable, then block pointer, keyboard and form behavior in code and style the state explicitly. The rules are in [semantics-and-aria.md](semantics-and-aria.md).

## Visible focus rings

Style `:focus-visible`, not bare `:focus`. Keyboard users get a ring and mouse users usually don't. Prefer the browser's unmodified indicator.

A custom ring needs a project focus token or another explicit color. It must reach 3:1 against every adjacent color it crosses, `currentColor` included, under 1.4.11. A `2px` solid perimeter with a 3:1 change of contrast is the 2.4.13 AAA target. Never use `outline: none` without a verified replacement, and preserve system colors in forced-colors mode.

A focused element must never sit fully hidden behind a sticky header, footer or banner (2.4.11). Give the scroller `scroll-padding-top` equal to the sticky header's height. Recipes are in [focus-and-keyboard.md](focus-and-keyboard.md).

## Full keyboard support

Every pointer interaction needs a keyboard path. Follow the ARIA APG patterns: Escape closes overlays, arrow keys move within composite widgets, Tab moves between widgets, Enter and Space activate buttons.

Use only `tabindex="0"` to join the natural tab order and `tabindex="-1"` for programmatic focus. Positive values break that order. Composite widgets use roving tabindex, where the active item is `0` and every other is `-1`. Where focus must stay in an input, as in a combobox, use `aria-activedescendant` instead. Key maps per widget are in [focus-and-keyboard.md](focus-and-keyboard.md).

## Trap and restore focus

Prefer `<dialog>` opened with `showModal()`, which makes the background inert and handles Escape. A custom overlay sets `inert` on the background, `role="dialog"` and `aria-modal="true"` on itself. Either way, move focus inside on open and return it to the trigger on close.

Client-side route changes reset nothing. Update `document.title` and move focus to the new view's `<h1>` or `<main>`. Both recipes are in [focus-and-keyboard.md](focus-and-keyboard.md).

## Minimum hit area

WCAG 2.5.8's Level AA baseline is a 24×24 CSS-pixel target, or one of its exceptions. Aim for 44×44px on touch and 40×40px on desktop where density permits. Extend with a pseudo-element when the visible element should stay smaller.

Never let extended hit areas overlap. Give decorative layers `pointer-events: none`, so a glow never swallows the clicks meant for the control beneath it.

Every drag interaction needs a single-pointer alternative, such as buttons or a menu that reorder or move the same item (2.5.7). Sizes, exceptions and collision rules are in [hit-areas.md](hit-areas.md).

## Label and type every control

Every input gets a `<label for>` or a wrapping `<label>`. A placeholder is never a label. Label and control share one hit target, with no dead zone between a checkbox and its text.

Add a valid `autocomplete` token and a descriptive `name` attribute, plus the `type` and `inputmode` that summon the right keyboard. Never block paste; users paste passwords and one-time codes. See [forms.md](forms.md).

## Errors that announce

Validate on submit, never by disabling submit until the form is valid. Mark failing fields `aria-invalid="true"`, point `aria-describedby` at the inline error text and focus the first invalid field. Submit behavior while the request runs is in [forms.md](forms.md).

## Accessible names everywhere

Icon-only buttons need a descriptive `aria-label`. Visible label text must appear in the accessible name. Decorative elements get `aria-hidden="true"`, never on a focusable element.

## Don't rely on color alone

Status needs a redundant cue: an icon, text or an underline alongside the color (1.4.1).

This skill decides which contrast requirement applies:

| Criterion | Applies to | Minimum |
| --- | --- | --- |
| 1.4.3 AA | Text | 4.5:1 |
| 1.4.3 AA | Large text, at least `24px` or `18.67px` bold | 3:1 |
| 1.4.11 AA | UI component boundaries, states and meaningful graphics | 3:1 |

Inactive controls and logos are exempt. Use `better-colors` to measure the rendered pair. When it fails, report the pair and the criterion it misses, and leave the colors alone unless asked.

## Honor prefers-reduced-motion

Wrap motion in `@media (prefers-reduced-motion: no-preference)` so it is opt-in. Under reduced motion, replace slides and scales with opacity crossfades, and kill parallax and autoplay entirely. See [motion-and-zoom.md](motion-and-zoom.md).

## Nothing the user needs runs on a timer

Anything moving, blinking or updating on its own for more than 5 seconds needs a visible pause control (2.2.2). Toasts carrying an action or an error stay until dismissed. The rules are in [motion-and-zoom.md](motion-and-zoom.md).

## Announce dynamic content

Three mechanisms, three jobs. `aria-describedby` carries field-specific validation. A polite live region (`role="status"`) carries non-urgent updates not tied to a control, such as toasts and result counts. `role="alert"` carries urgent untied errors and nothing else.

Repeated polite announcements need a stable empty region rendered before its text updates. Dynamically inserted alerts vary in support, so test them on the screen readers you target. See [screen-readers.md](screen-readers.md).

## Alt text by purpose

Decorative images get `alt=""`. Informative images describe the meaning. Functional images describe the action, never the picture. The full table is in [screen-readers.md](screen-readers.md).

## Structure is navigation

Use headings that describe their sections and form a coherent outline. Expose one visible primary `<main>` landmark. When repeated navigation or chrome precedes it, make a "Skip to content" link the first focusable element. Anchored headings get `scroll-margin-top`.

## Survive zoom and text resize

Text must survive 200% resize (1.4.4), and the page must reflow at 320px width without horizontal scrolling (1.4.10). Text containers take `min-height`, not `height`, and `better-layout` owns the rest of that fix. Never set `maximum-scale=1` or `user-scalable=no` in the viewport meta. iOS input zoom is fixed with `better-typography`'s `16px` rule instead.

## Before you finish

| Pattern | Fix |
| --- | --- |
| `outline: none` or `outline-none` with no `focus-visible` replacement nearby | Restore the browser ring or add a verified custom one |
| `<div onClick` or `<span onClick` | Use `<button>`, or `<a href>` when it navigates |
| `role="button"` or `role="tab"` with no `onKeyDown` | Use the native element, or implement the APG key map |
| `tabIndex={1}` or any positive `tabindex` | Fix the DOM order and use `0` |
| `disabled={!isValid}` on a submit button | Keep it enabled and validate on submit |
| `{msg && <div role="status">`, region mounted with its text | Render the empty region first and update its text |
| `aria-live="assertive"` on a success toast | `role="status"` |
| `<img` with no `alt` attribute | `alt=""` if decorative, otherwise describe the purpose |
| `aria-label` whose text omits the visible label | Start the name with the visible text |
| `aria-hidden` on an ancestor of a button, link or input | Remove it, or make the subtree inert |
| `maximum-scale=1` or `user-scalable=no` | Remove it |
| `position: sticky` header with no `scroll-padding-top` on the scroller | Pad the scroller by the header height |
| Tooltip on a natively `disabled` control | Text beside it, or `aria-disabled` so it stays focusable |

From transitive-bullshit/skills, MIT.

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