Wcag Accessibility

WCAG Accessibility (EN 301 549 / European Standard)

The Standard

The European Accessibility Act (EAA) requires digital products and services in the EU to meet EN 301 549, which references WCAG 2.2 Level AA as the technical baseline. This is not optional — it is a legal requirement for products operating in the EU market.

Default: always build to WCAG 2.2 AA. Deviating requires explicit, documented justification. Do not skip accessibility requirements because of timeline pressure or design preference.

WCAG 2.2 AA organises requirements under four principles: Perceivable, Operable, Understandable, Robust.

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Perceivable

Users must be able to perceive all content and UI components.

Colour Contrast

| Context | Minimum ratio | Enhanced (AAA) | |---|---|---| | Normal text ( element: or `

• Mark inline content in a different language with lang on that element

Labels and Instructions

• Every form input must have a visible label — not just a placeholder (placeholders disappear on input)
• Required fields must be indicated — do not rely on colour alone; add an asterisk and a legend
• Error messages must be associated with their input via aria-describedby

Predictability

• Components that look the same must behave the same (see Consistency and Standards)
• Navigation must appear in the same location across pages
• Opening a new tab or window must be communicated in advance

Error Identification

• Form validation errors must identify which field failed
• Errors must be described in text — not only by colour or icon

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Robust

Content must be interpreted reliably by assistive technologies.

Semantic HTML

Use the correct HTML element for the job. Semantics convey role, state, and structure to screen readers for free.

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ARIA — Use Sparingly

ARIA supplements HTML semantics where native elements fall short. It does not fix broken HTML.

Rule: no ARIA is better than incorrect ARIA. Incorrect ARIA actively breaks screen reader output.

Required patterns:

• aria-label or aria-labelledby for components with no visible text label
• aria-expanded on toggles, accordions, and dropdowns
• aria-live regions for dynamic content updates (toast notifications, search results)
• role="dialog" with aria-modal="true" on modal overlays
• aria-current="page" on the active navigation item

Status Messages

Dynamic updates (success toasts, loading states, error counts) must be announced to screen readers via aria-live or role="status" — they will not be announced automatically unless the focused element changes.

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The Disabled Element Exception

WCAG 1.4.3 explicitly states: "Text or images of text that are part of an inactive user interface component… have no contrast requirement."

This means:

• Disabled buttons, inputs, and links may use low-contrast text and colours
• The visual dimming of disabled states is both correct and compliant
• Do not add artificial contrast to disabled elements — the reduced contrast communicates "this is unavailable"

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Review Checklist

| Area | Check | |---|---| | Contrast | All active text ≥ 4.5:1 (normal) or 3:1 (large/UI) | | Contrast | Disabled elements exempt — intentionally low contrast is fine | | Colour | Colour is never the only information carrier | | Keyboard | All interactive elements reachable and operable by keyboard | | Focus | Visible focus indicator on every interactive element | | Touch | Interactive targets ≥ 44×44px on touch surfaces | | Labels | Every input has a visible label (not just placeholder) | | Errors | Validation errors identify the field and describe the problem in text | | HTML | Semantic elements used correctly; ARIA only where needed | | Language | lang attribute set on ` | | Skip link | "Skip to main content" as first focusable element | | Live regions | Dynamic updates announced via aria-live or role="status"` |

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: dembrandt
• Source: dembrandt/dembrandt-skills
• License: MIT

Install and usage instructions live in the source repository linked above.