A Practical Guide to Tailwind CSS v4

Tailwind v4 moves configuration into CSS itself via @theme, which means design tokens live next to the styles that use them instead of in a separate JS config file. The new engine is also noticeably faster on incremental builds, which matters most on larger component libraries.

The practical upshot: fewer context switches between a config file and your markup, and a build step that keeps up with editing speed even on bigger projects.