Bootstrap

Bootstrap is a open-source collection of tools for creating browser sites and applications.

Free Open Source Self-Hosted JavaScript HTML5 Boilerplate

Foundation

Foundation is an easy to use, powerful, and flexible framework for building rapid prototypes and production code on any kind of device.

Free Open Source Web

Materialize

Materialize is a modern responsive CSS framework based on Material Design by Google

Free Open Source Web

Bourbon

Bourbon - A simple and lightweight mixin library for Sass / CSS.

Free Open Source Mac OS X Windows Linux Sass

Purecss

A set of small, responsive CSS modules that you can use in every web project.

Free Open Source Web

GroundworkCSS

GroundworkCSS is a 100% free and open source responsive HTML5, CSS and JavaScript Framework.

Free Open Source Web Self-Hosted

Spectre.css

Lightweight, responsive and modern CSS framework for faster and extensible development.

Free Open Source Web Self-Hosted

Refills

Refills are prepackaged patterns and components, built on top of Bourbon, Bitters and Neat.

Free Open Source Web

Blaze CSS

Open source modular CSS framework providing great structure for building websites quickly.

Free Open Source Mac OS X Windows Linux Self-Hosted

yeti.css

yeti.css is a pattern library consisting of lightweight, reusable modules. It has been built to reflect &yet's visual and branding guidelines.

Free Open Source Mac OS X Windows Linux Self-Hosted

inuit.css

inuit.css is a lightweight, constantly updated CSS framework which provides you with a pragmatic and feature-rich starting point for all your projects. It is crammed...

Free Open Source Web