Themes
6 in the family and 1 outside it. A theme sets colour, a type pair, a radius base and a density. Everything else is shared.
The family
Reference
Core
Bricolage Grotesque and IBM Plex Sans
Condiment Gallery
Condimental
Young Serif and Figtree
Time Dissonance
Dissonance
Libre Baskerville and Libre Franklin
Household app
Household
SF Pro Rounded and SF Pro Text
Ritual
Routine
Fraunces and Hanken Grotesk
Eye for Type
Specimen
Source Serif 4 and Source Sans 3
Family members take everything: the primitives, base.css, the type scale and the whole interaction layer.
Outside the family
Brookwood is the one app made for people who have never seen any of the others. It takes the primitives (spacing, type scale, motion, focus) and none of the shared components. No gradient text, no Pro button, no thinking shimmer, because those would make it look like part of a portfolio.
Dark sets
A theme can have a dark block. It can only override colours the theme already has, and it's used when the device is in dark mode. Set data-ds-mode="light" or "dark" on <html> to force one. Household has one so far.