ARIA — the semantic states State rides the attribute the screen reader hears; the engine styles the same attribute. No class ever duplicates these.
aria-pressed Toggles. Standalone button lifts + full ink; a .button-group member goes full-blast.
aria-current="page" Where you ARE — nav items, menu rows, breadcrumbs.
aria-selected Tabs and pickable rows — the underline follows the attribute.
aria-disabled · disabled Drained ink + not-allowed cursor; aria-disabled keeps the element focusable for AT.
tag aria-disabled
aria-invalid The label composition locks the danger hue and paints the hint at full ink.
The rest of the shell's ARIA aria-label on every icon-only control (the ratchet's icon boxes stay mute without it) · aria-hidden on decorative glyphs · aria-busy while a rocket fetches · aria-haspopup + aria-controls on the openers · aria-activedescendant in the command palette.