TreeTable is DataTable with treeMode enabled, so it inherits every theme token, CSS class, and pass-through target from the DataTable theme.

See DataTable Theming for the full reference.

Tree-specific parts#

These are the parts you'll most likely customise when theming TreeTable:

• DataTable.RowToggle — the chevron button on the first column (data-part="row-toggle").
• DataTable.RowToggleIndicator — the icon slot, matched by match="expanded" and match="collapsed".
• Row-level _treeLevel drives the default left padding via CSS. Override per-level spacing by styling on the aria-level="<n+1>" attribute rendered on <tr>.