Upgraded the project to Tailwind CSS v4 today. The new CSS-first configuration approach is a breath of fresh air — no more tailwind.config.js for most use cases.

The @theme directive for defining design tokens directly in CSS feels much more natural. Performance improvements are noticeable too, especially during development with faster HMR.

More detailed notes captured in Tailwind CSS v4 — particularly the breaking changes around dark mode and @apply.