This project is using Sass to generate it's CSS. Sass is a CSS preprocessor that allows for faster development of CSS. For more information about sass: http://sass-lang.com To use sass all you need to do is enter: $ gem install sass We are also using Bourbon with sass. They are a generic set of mixins, and functions that allow for more rapid development of CSS3. Find out more about bourbon here: https://github.com/thoughtbot/bourbon Then to generate Sass files cd to templates directory and watch the sass files for developement: $ sass --watch sass:../static/css/ -r ./sass/bourbon/lib/bourbon.rb To generate a compressed css file for production: $ sass --watch sass:../static/css/ -r ./sass/bourbon/lib/bourbon.rb --style :compressed These will automatically generate the CSS files on save.