Tree

Open “Tree & validation” in a new tab ↗

Markup

.tree + [data-tree] with nested .tree-item > .tree-row (and a .tree-children list for branches). Full keyboard navigation:

Key	Action
↑ / ↓	move between visible rows
→	expand (or move into children)
←	collapse (or move to parent)
Enter	activate the row

Use aria-expanded on each branch .tree-item; leaf rows use .tw.leaf for alignment.