Plan step 19, containment.md C-08, C-21, C-22 and C-16. The segmented
fill was declared unlayered, so it beat every state layer in
@layer components and a segmented row lit up for nothing: it now sits in
the layer, `:where()`d to weigh nothing, ahead of the state rules. Its
tone is `surface`, which is ListTokens' ItemSegmentedContainerColor, and
a keyboard-focused row morphs to the large corner like a pressed one.
`<x-list dividers>` draws ListTokens' 16dp-inset rule instead of a
full-bleed `divide-y`.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9
