tailwindcss

Summary This PR enables coverage for Sass/SCSS usage with interpolation () in the codemod. The codemod already handles in , but the corresponding test was previously skipped with a TODO. This change removes the skip and updates the comment so CI will catch regressions and the supported behavior stays documented. Test plan Updated the existing unit test in by un-skipping the case and verifying the expected output snapshot. Local verification (limited in this environment): ensured lint/pre-commit formatting passes and that the change is isolated to tests only. Recommended CI/local verification in a full dev environment (with Rust toolchain available): ```sh pnpm install pnpm test

What version of Tailwind CSS are you using? tailwindcss@4.2.0 What build tool (or framework if it abstracts the build tool) are you using? "next": "16.1.6", What version of Node.js are you using? v24.12.0 What browser are you using? N/A What operating system are you using? macOS Describe your issue After running the npx @tailwindcss/upgrade command, I can't perform any further actions. Flow: Need to install the following packages: @tailwindcss/upgrade@4.2.1 Ok to proceed? (y) y It gets stuck at this stage

Summary This PR adds a new package that provides a dedicated webpack loader for Tailwind CSS v4. This loader works with both standard webpack and Turbopack's webpack loader compatibility layer. Why a dedicated loader? The current webpack integration uses + . While this works, a dedicated loader: Eliminates PostCSS as a middleman - works directly with CSS strings (no AST conversions) Simpler and more efficient - follows the same pattern as Better for Turbopack** - gives direct control over dependency reporting via webpack's loader API How it works The loader mirrors the Vite plugin's approach: 1. Uses from to parse CSS and resolve directives 2. Uses from to scan content files for utility candidates 3. Reports dependencies via and 4. Optionally optimizes output with Lightning CSS Usage Options The base directory to scan for class candidates (defaults to ) Whether to optimize/minify the output CSS (defaults to in production) Files added New package Main loader implementation CommonJS entry point for webpack compatibility , , , Integration tests Added webpack override for transitive dependencies Test plan [x] Build test - verifies basic compilation [x] Watch test - verifies HMR when adding new Tailwind classes [x] test - verifies directives work correctly [x] Optimization test - verifies minification works

What version of Tailwind CSS are you using? v4.2.0 What build tool (or framework if it abstracts the build tool) are you using? tailwindcss-ruby 4.2.0 What version of Node.js are you using? N/A What browser are you using? N/A What operating system are you using? macOS Reproduction URL https://github.com/lk-umetsu/tailwind-ruby-heredoc-issue Describe your issue Reproduces an issue in tailwindcss-ruby v4.2.0 where class names inside Ruby heredoc interpolation (#{...}) are not scanned, while the same pattern in regular strings works fine. Expected behavior: String literals inside interpolation within a heredoc should be detected as class candidates, consistent with how they are handled in regular string interpolation.