Accessibility and interaction rules for building UIs. Use when building forms, buttons, navigation, animations, or any interactive elements.
Concise rules for building accessible, fast, delightful UIs. Use MUST/SHOULD/NEVER to guide decisions.
:focus-visible)outline: none without visible focus replacement<input> font-size ≥16px to prevent iOS zoomtouch-action: manipulation to prevent double-tap zoomautocomplete + meaningful name; correct type and inputmode<a> for navigation (support Cmd/Ctrl/middle-click)<div onClick> for navigationaria-live for toasts/inline validationprefers-reduced-motiontransform, opacity) onlytop, left, width, height)transition: all—list properties explicitlyenv(safe-area-inset-*))<title> matches current contextfont-variant-numeric: tabular-nums for number comparisonsaria-labelcolor-scheme: dark on <html> for dark themes<meta name="theme-color"> matches page background<select>: explicit background-color and color