Visual system · The specifications · Element

The colour

The palette, in exact values for every medium it is used in.

The part

What it is

Each colour needs a value per medium, a role, and a rule about where it may be used. A palette without roles becomes a set of options.

Accessibility contrast belongs here rather than being discovered later: a palette that fails contrast is a palette that will be quietly departed from.

The smallest level

The attributes it carries

Each attribute is one of the framework’s shared types. What a date is, and how it is written, is defined once for the whole model — the note here says what it means in this particular place.