GitHub - bitjaru/styleseed: Claude Code & Cursor design system. Stop generating ugly AI UI. 69 design rules + 48 shadcn components + Toss/Stripe/Linear/Vercel/Notion brand skins. Tailwind v4 + Radix.

StyleSeed is an open-source design system built specifically for AI coding tools like Claude Code and Cursor. It provides 69 visual design rules, 48 React components (built on shadcn/ui and Radix UI), and 13 slash-command AI skills to help AI-generated UIs look professional rather than generic. The system separates a brand-agnostic 'engine' (design judgment rules) from interchangeable 'skins' (theme.css files for brands like Toss, Stripe, Linear, Vercel, and Notion). Setup options range from an interactive wizard to simply pointing AI at the GitHub URL. The stack uses React 18, TypeScript, Tailwind CSS v4, and Vite 6.