Split button
A composite action control: a primary <button> paired with a
dropdown toggle that opens a menu of alternative actions. Both segments are
.c-button, so every variant, state, and density tier works out of the
box. This component adds only the layout glue, the seam divider, and the
Popover API menu.
Variants
Set the same data-variant on both buttons so the fill matches
across the seam.
With icons
States
Density
Sizing is driven by --pl-control-block-size on an ancestor's [data-density].