Accessibility

Our target

WCAG 2.2 Level AA, with body copy held to the stricter 7:1 AAA ratio. Contrast is validated at build time against every token pair that carries text, and the build fails on a violation. Every interactive component — the size selector, the materials matrix and its category tabs, the command bar, the calculators, the mobile menu and the language switch — is operable from the keyboard alone. Focus indicators are never removed, and every anchor target is offset below the sticky header so a focused element is never hidden behind it.

Specific commitments

• The materials matrix never signals accepted or prohibited by colour alone — every state carries an icon and a text label.
• Every chart has an accessible name and a full data table beneath it.
• Calculators accept typed values and arrow keys — no interaction requires dragging.
• Help and contact links sit in the same footer position on every page.
• Reduced-motion and increased-contrast preferences are honoured. Increasing contrast raises the dim tones rather than inverting the page, because inverting would break the colour relationships the status colours depend on.
• The category tabs on the materials matrix are a real tablist: arrow keys move between them, Home and End jump to the ends.
• This site has one visual mode — a dark canvas — so there is no theme toggle to operate.

Known gaps

Automated checks run on every build; manual screen reader passes are performed per template rather than per page, so an individual page may carry an issue the template test did not surface. Charts rely on a third-party library whose canvas output is not itself navigable — the data table beneath each one is the accessible equivalent, and it is always present. There is no light mode: the design system defines a single dark surface, so a reader who needs a light background will need browser-level or OS-level inversion.