Colour, type and spacing as variables, not hard-coded values.
Wraps that own the container so blocks do not have to.
Script loads only where the markup that needs it exists.
Focus rings, reduced motion and keyboard paths in the defaults.
Filler so the stage behaves like a page — something to scroll, and something for a translucent bar to pass over. The component above is the subject; this is only the ground it stands on.