The gutter sits 100 px to the left of the tree canvas on md+ viewports
(hidden entirely below md to preserve scrollable area on phones — see
spec's deliberate dual-audience trade-off). Per occupied generation
row it draws:
- A full-width decorative stripe rect alternating transparent and
var(--c-gutter-stripe). aria-hidden because it carries no meaning.
- The label `G{n}` at the left edge, sourced from the un-shifted
node.generation value (never the post-normalise rank), wrapped in
`<g role="text" aria-label="Generation N">` so screen readers
announce the full word instead of "G three".
CSS adds --c-gutter-stripe in both the light root and the dark mode
blocks (8% / 14% mint over canvas — decorative contrast carve-out).
Browser tests cover label rendering, the ARIA wrapper, and the
viewport-below-md absent-gutter path via a matchMedia stub. Existing
StammbaumTree structural-invariant tests still pass since none of
them assert anything inside the gutter region.
Refs #689
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Adds selected-node primary fill, birth/death year combinations,
node click and Enter/Space/other-key handling, dashed/solid spouse
line, single-parent connector, focus ring on focus + blur, aria
labels and aria-expanded reflection, accent stripe on selected node.
13 new tests covering ~30 branches in the node-render path.
Refs #496.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
