The most popular HTML, CSS, and JavaScript framework for developing responsive, mobile first projects on the web. http://getbootstrap.com

Semantic UI, converted to Sass and ready to drop into Rails, Compass, or Sprockets.

twitter-bootstrap-rails project integrates Bootstrap 5 CSS toolkit for Rails 8, 7, 6, 5 (also supports) Asset Pipeline

bootstrap-sass is a Sass-powered version of Bootstrap 3, ready to drop right into your Sass powered applications.

A lightweight CSS framework for developing mobile-first projects in Ruby on Rails.

Stylish is a theming toolkit based on semantic-ui

twitter-bootswatch-rails gem integrates TWBS Bootstrap for Rails Asset Pipeline with less-rails

FontAwesome toolkit for twitter-bootswatch-rails gem for Rails Asset Pipeline with less-rails

twitter-bootswatch-rails-helpers gem provides common view helpers for use with the twitter-bootswatch-rails & less-rails gems