Every site on the network ships the same twenty-four colour themes and the same builder, because they share one design system. This copy of it repaints this portal only: your choice is stored under this site’s own key, in this browser, and travels nowhere.
The builder loads with the page. If you are reading this line, JavaScript has not run yet — the twenty-four preset themes in the header’s display settings work without it.
Preview
Body text on the page ground, with a link in it, so you can see both at once before you keep a palette.
Legibility is scored, not guessed
Each pairing the builder produces is measured against the WCAG contrast formula as you move the swatches, so you find out that a palette is unreadable before you keep it rather than afterwards. The same measurement runs in this network’s CI over all twenty-four presets.