GenCSS
GenCSS builds the design system the rest of the toolkit runs on. Give it a handful of colours and a type ratio and it generates a complete globals.css (an OKLCH palette with consistent shades and transparencies, a fluid type scale, spacing, buttons, links and forms) split into primitives and tokens so a single remap re-themes everything.
What GenCSS does
OKLCH throughout
Shades and tints are derived in a perceptual colour space, so a light blue never turns neon on you.
Two layers, on purpose
Primitives hold the colour; tokens point at the primitives. Change what a token points at and the theme follows.
Regenerates safely
Your own additions live in USER blocks that survive every save.
Try GenCSS
It runs on your own machine, with your data in a file you can open. If it turns out not to suit how you work, tell us.