Tailwind CSS v4: What Changed and Why It Matters

Rust-powered Oxide engine cuts build times from ~3 seconds to under 1 second for faster development. Design tokens now defined in CSS via @theme instead of tailwind.config.js for better organization. Custom utilities created inline with @utility directive without needing plugins or complex configuration. Automatic content detection eliminates manual file path configuration and related debugging issues. CSS @layer organization ensures proper cascade without !important and prevents style conflicts automatically. Tailwind v4 shipped with a completely rewritten engine, and the migration isn't just a version bump. After rebuilding RAXXO Studio's entire styling system on v4, here's what actually changed in practice - not the marketing overview, but the real differences you'll hit in daily development. The Engine Rewrite Tailwind v4 replaced the old JavaScript-based build system with a Rust-powered engine called Oxide. The practical impact: builds are significantly faster. On the RAXXO codeba