Adjusting Tailwind CSS v4 not to strip utility classes in combination with @apply in CSS Modules, you have to pick up your. css in content array of tailwind. config. js. For performance reasons, Tailwind no longer scans CSS for files by default. By explicitly adding '. /src/*/. css files to be processed by Tailwind on build time. That's important when you use @applying within module CSS files to cover off missing styles like bg-slate-700.

['. /src//*. {js,ts,jsx,tsx}', '. /src//*. css']