Tailwindcss

Tailwind CSS is a utility-first CSS framework: rather than inventing class names and tending a separate stylesheet, you compose small single-purpose utilities straight into the markup and never leave your HTML. Because each utility carries one fixed meaning, a design stays consistent by construction and the hours once spent naming things mostly disappear.

A design system of spacing, color, typography and responsive scales ships with it, meant to be extended rather than fought, and any style you never use is absent from the build output. Adoption is unusually wide for front-end tooling, past 96,000 stars on GitHub, with component libraries, editor plugins and framework integrations stacked around it. Documentation sits at tailwindcss.com, and Tailwind Labs maintains the project under the MIT license.