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

Semantic UI

Semantic empowers designers and developers by creating a shared vocabulary for UI.

Free Open Source Web

UIKit

A lightweight and modular front-end framework for developing fast and powerful web interfaces. ui framework full HTML / CSS, javascript component , form, theme , dropdown , responsive ... More full than bootstrap or foundation

Free Open Source Web

Polymer

Polymer is a library that uses the latest web technologies to let you create custom HTML elements. Build anything from a button to a complete application as an encapsulated, reusable element that works across desktop and mobile.

Free Open Source Mac OS X Windows Linux

Skeleton

Skeleton is a small collection of CSS & JS files that can help you rapidly develop sites that look beautiful at any size, be it a 17" laptop screen or an iPhone.

Free Open Source Web

HTML5 Boilerplate

A rock-solid default for HTML5 awesome. HTML5 Boilerplate is the professional badass's base HTML/CSS/JS template for a fast, robust and future-proof site.

Free Open Source Web

Purecss

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

Free Open Source Web

Metro UI CSS

Metro UI CSS a set of styles to create a site with an interface similar to Windows 8.

Free Open Source Web jQuery LESS

Slides Framework

Slides is a simple and powerful HTML and CSS framework that lets you easily build beautiful static websites thanks to a flexible modular setup.

Commercial Self-Hosted

Flat UI Pro

Flat UI Pro is made on the basis of Twitter Bootstrap in a stunning flat-style, and the kit also includes a PSD version for designers. Flat UI Pro contains a huge number...

Commercial Web

HTML KickStart

HTML KickStart is a ultra–lean set of HTML5, CSS, and jQuery (javascript) files, layouts, and elements designed to give you a headstart and save you a lot of hours on...

Free Web

GroundworkCSS

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

Free Open Source Web Self-Hosted

MUI

MUI is a lightweight HTML/CSS/JS framework that follows Google's Material Design guidelines.

Free Open Source Web

Spectre.css

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

Free Open Source Web Self-Hosted

Material Design Lite

Google's front-end web framework for building sites to the Material Design specification.

Free Open Source Web GitHub

Picnic CSS

Unpack your meal and get coding. An invasive CSS library to get your style started.

Free Open Source Self-Hosted CSS

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