Tailwind Theme Builder

This handles the full Tailwind v4 migration dance: CSS variable setup, dark mode wiring, and shadcn/ui integration without the usual footguns. The four-step CSS architecture is mandatory and well-documented here because v4 breaks if you nest things wrong or double-wrap hsl() values. What's useful is the troubleshooting table covering all 18 gotchas, from variables being ignored when :root sits inside @layer base to the PostCSS versus Vite plugin confusion. Reach for this when you're migrating from v3, setting up a new themed project, or debugging why bg-background isn't generating. It's opinionated about semantic tokens and includes the complete theme provider and toggle components.