Why I kept three sites in one repo

The monorepo decision was not ideological. It was the answer to one specific question: how do I make the corporate site, the lab, and the personal site look like they belong together without copy-pasting the design tokens into three places that would inevitably drift?

The naive answer is a single CSS file imported by all three. The problem with that is each site has a different voice. The corporate site needs to look like a UK limited company. The lab needs to look like a marketplace. The personal site needs to look like a person. You cannot serve all three with one accent color.

The fix is the override pattern. The shared package defines every token. Each site has a small override.css that re-declares the tokens that need to change. The shared components read tokens, not hardcoded colors, so they re-skin themselves. The result is a single source of truth for the family DNA, and three sites that each have their own accent, their own radius, their own mood.

The trick that makes it work: a component that hardcodes a color is not eligible for the shared package. A component that reads from a token is. The hard constraint catches the things that would otherwise leak into three slightly different shades of green.