Tree Grid

The component is self-contained: one file, no dependencies, the palette in --vibeui-datagrid-024-*. A client component: useState holds the list of expanded branches, and a walk of the tree flattens it into a plain list of rows. The level is declared by the markup: the row carries aria-level and the parent aria-expanded, and the indent arrives through the --vibeui-datagrid-024-depth variable and is multiplied by the step. A parent's total is always computed from its descendants recursively: a collapsed branch without a sum of its own hides the data rather than folding it. The disclosure button carries its own aria-label with the name of the branch, and the arrow is turned with transform. The scrolling is moved into a container with role=region and tabindex=0. The theme comes from the surrounding color-scheme through light-dark(): by default the grid lays no panel under itself, it sits directly on the page background and darkens along with it.