UnoCSS is the instant atomic CSS engine, that is designed to be flexible and extensible. The core is un-opinionated and all the CSS utilities are provided via presets.

Tauri is a framework for building tiny, blazingly fast binaries for all major desktop platforms. Developers can integrate any front-end framework that compiles to HTML, JS and CSS for building their user interface. The backend of the application is a rust-sourced binary with an API that the front-end can interact with.

Paged.js is a free and open source JavaScript library that paginates content in the browser to create PDF output from any HTML content. This means you can design works for print (eg. books) using HTML and CSS!

Paged.js follows the Paged Media standards published by the W3C

A utility-first CSS framework packed with classes like flex, pt-4, text-center and rotate-90 that can be composed to build any design, directly in your markup.

CSS Animation Library for eccentric web developers.

Ink provides the same component-based UI building experience that React offers in the browser, but for command-line apps. It uses Yoga to build Flexbox layouts in the terminal, so most CSS-like props are available in Ink as well. If you are already familiar with React, you already know Ink.

a ridiculously small responsive css framework

98.css is a CSS library for building interfaces that look like Windows 98.

Minimalistic icon library Designed by code, Customizable & Retina-Ready icons — built 100% in pure CSS. Easy integration: Embed, NPM & API

Prettier is an opinionated code formatter. It enforces a consistent style by parsing your code and re-printing it with its own rules that take the maximum line length into account, wrapping code when necessary.

PurgeCSS is a tool to remove unused CSS. It can be part of your development workflow.

Easy control over your dark mode in a web environment

Support tables for HTML and CSS in emails.

Skeleton: A Dead Simple, Responsive CSS Boilerplate for Mobile-Friendly Development

Blazing fast, zero configuration web application bundler

emotion is a high performance, lightweight css-in-js library that supports both string and object based styles.

A free and modern UI toolkit for web makers based on the popular Bootstrap 4 framework.

Styletron is a universal CSS-in-JS engine built from the ground up for high-performance.

minimal, responsive, style-agnostic CSS framework

A tool for developing responsive websites crazy-fast.
Open sourced : https://github.com/kitze/sizzy