Tailwind scans your project for utility classes to generate minimal CSS. It basically tries to strip out everything that you’re not using and only include what you are using.

• Treats files as plain text (no code parsing)
• Looks for tokens resembling class names
• Generates CSS for recognized utilities

Tailwind scans all files except the usual suspects:

• .gitignore entries
• Binary files (images, videos, zips)
• CSS files
• Package manager lock files

Explicit Source Registration

For files missed by automatic detection (e.g., external libraries), use @source to register paths:

@import 'tailwindcss';
@source "../node_modules/my-library/src/components";

Set base path with source():

@import 'tailwindcss' source('./src');

Ignore paths with @source not:

@import 'tailwindcss';
@source not "../legacy";

Disable automatic detection: source(none).

Inline Safelisting

Force generation of specific classes with @source inline() (replaces Tailwind 3’s safelist array):

@import 'tailwindcss';
@source inline("inline-block");

Include variants:

@import 'tailwindcss';
@source inline("underline", "hover:underline", "focus:underline");

Or use brace expansion:

@import 'tailwindcss';
@source inline("{hover:,focus:,}underline");

Generate ranges:

@import 'tailwindcss';
@source inline("{hover:,}bg-red-{100..900 by 100,50,950}");

Exclude classes with @source not inline():

@import 'tailwindcss';
@source not inline("{hover:,focus:,}bg-red-{100..900,50,950}");