Design System Architecture: Theming, Experiments, and Keeping It Maintainable

What it is — A practical look at the architectural decisions mature design systems face when scaling across teams and platforms: managing experiments, theming, web/app library splits, and token granularity.

Key points

• Treats component sprawl as a governance problem, not a technical one — Figma’s Extended Collections let value-level experiments run independently, but structural changes need a formal decision process to avoid fragmentation.
• Recommends keeping seasonal/brand variants as separate, toggleable libraries distinct from modes (light/dark), and warns that splitting web and app libraries is harder than it looks — don’t do it until there’s both structural necessity and dedicated ownership.
• On tokens, start semantic and add component-level specificity only when experiments demand it; on AI tooling specifically, argues today’s single-file structures suit AI generation but multi-file structures still scale better for human teams, so prioritise team workflow over premature AI optimisation.