Pick a base gray, a primary color, and a corner radius.
NL
--color-accent (and its dark-mode variant),
picked from Tailwind's own palette. Base gray works by reassigning
Tailwind's --color-zinc-* variables, since every
HarmonyUI component is hardcoded to zinc under the hood, so no
component class ever changes. Radius drives the whole rounded-* scale
from a single --radius variable.