Foundations
The primitives — colour, typography, spacing, shape, and motion. Everything else composes from these.
Foundations are the values the rest of the system is built from. They are
deliberately small in number and fixed: a component may choose which token to
use, but it does not invent new ones.
Three 12-step scales in two modes, their step roles, and the contrast rules that govern them.
Three typefaces, three jobs, and a fixed type ramp.
The 4px spacing base, the radius and elevation ladders, and the motion tokens.
The four breakpoints, how the 12-column grid collapses, touch-target sizes, and the mobile navigation pattern.