Aperture Accordion

The component is self-contained: one file, no dependencies, its own palette in local variables --vibeui-accordion-012-*. Native <details>/<summary> hold the disclosure, so the keyboard, find-on-page and the state before hydration all work without JS. The component has no accent colour: the states differ by the contrast of material and light, so the focus ring takes the text colour and is drawn inwards on the slab. The dark branch is not an inversion of the light one — on light the cut lets the light in and the well is brighter than the slab, on dark the well is darker and the edge catches a highlight from above. The material colour is set by the slab prop, and the row highlight and the rule between sections are derived from it by mixing. Padding and type size are computed from the component's own width through @container.