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

Minimal CSS Framework for semantic HTML

A showcase of problems once hard or impossible to solve with CSS alone, now made trivially easy with Flexbox.

The most advanced, yet intuitive, grid system available for Sass or Stylus

Simple media queries in stylus

Arc theme with Flatabulous window controls.

Sleek, intuitive, and powerful Google styled front-end framework for faster and easier web development

Cloudinary JavaScript library

HTML, CSS, and JS toolkit from Twitter – Official Sass port:

YeSvelte UI component library for Svelte

BOOTFLAT is an open source Flat UI KIT based on Twitter Bootstrap 3 css framework. It provides a faster, easier and less repetitive way for web developers to create elegant web app.