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Tailwind CSS v4 - Workspace Package Configuration

Key: How to properly configure Tailwind v4 in a pnpm monorepo to scan CSS classes from workspace packages.

Problem​

When using Tailwind CSS v4's Vite plugin (@tailwindcss/vite) in a pnpm monorepo, external workspace packages (such as @viben/kanban, @viben/ui) are not automatically scanned for CSS classes.

This causes CSS classes used in these packages to be purged from the final build, breaking layouts and styles.

Symptoms​

  • Layouts silently fail (no build errors)
  • Grid layouts (inline-grid, grid-flow-col) don't work
  • Flex layouts behave abnormally
  • CSS properties like auto-cols-[280px] have no effect

Root Cause​

Tailwind v4 with the Vite plugin automatically detects content sources in the project, but:

  1. By default, it only scans files in src/
  2. Workspace packages symlinked via pnpm (node_modules/@viben/*) are not included
  3. CSS classes in external packages are purged because Tailwind doesn't know they exist

Solution​

Add @source directives in the CSS entry file to explicitly include workspace packages.

Example: apps/desktop/src/index.css​

@import "tailwindcss";

/* Scan Tailwind classes in workspace packages */
@source "../node_modules/@viben/kanban/src/**/*.tsx";
@source "../node_modules/@viben/ui/src/**/*.tsx";

@theme {
  /* ... theme configuration */
}

Key Points​

  1. Use node_modules paths - The path ../node_modules/@viben/kanban will correctly follow symlinks
  2. Include source files - Point to the src/ directory with TSX files, not the dist/ output
  3. Use glob patterns - **/*.tsx captures all component files

Verification​

After adding @source directives:

  1. Clear all caches:

    rm -rf apps/desktop/dist .turbo node_modules/.vite

  2. Rebuild:

    pnpm build --filter @viben/desktop

  3. Check CSS output:

    # Split minified CSS and search for classes
    cat apps/desktop/dist/assets/index-*.css | tr '}' '\n' | grep "inline-grid"

    Expected output:

    .inline-grid{display:inline-grid
    .auto-cols-\[280px\]{grid-auto-columns:280px
    .grid-flow-col{grid-auto-flow:column

CSS Classes Required for Horizontal Kanban Layout​

The kanban board requires these CSS classes to display horizontally:

ClassPurposeCSS Output
inline-gridMakes the container an inline griddisplay: inline-grid
grid-flow-colFlows items by columngrid-auto-flow: column
auto-cols-[280px]Sets column widthgrid-auto-columns: 280px
divide-xAdds vertical dividersborder-left-width: 1px
border-xAdds left/right bordersborder-left/right-width: 1px

If any of these classes are missing from the compiled CSS, the kanban will stack vertically instead of horizontally.

Common Mistakes​

Wrong: Using relative paths from src/​

/* This path may not resolve correctly */
@source "../../packages/kanban/src/**/*.tsx";

Correct: Paths through node_modules​

/* Follow symlinks through node_modules */
@source "../node_modules/@viben/kanban/src/**/*.tsx";

Wrong: Only scanning dist/​

/* dist/ contains compiled JS, not source code with class strings */
@source "../node_modules/@viben/kanban/dist/**/*.js";

Correct: Scan source TSX files​

/* Source files contain class string literals */
@source "../node_modules/@viben/kanban/src/**/*.tsx";
FilePurpose
apps/desktop/src/index.cssCSS entry point with @source directives
apps/desktop/vite.config.tsVite configuration with @tailwindcss/vite plugin
packages/kanban/src/kanban.tsxKanban component using grid classes

Debugging Tips​

  1. CSS file size changed? If the CSS file size increases after adding @source, it's working
  2. Same hash after rebuild? Cache not cleared - delete .turbo and dist/
  3. Classes still missing? Check if the glob pattern covers all files using those classes

Last Updated: 2026-02-28 Status: ✅ Production Fix