Sass is an extension of CSS3 which adds nested rules, variables, mixins, selector inheritance, and more. Sass generates well formatted CSS and makes your stylesheets easier to organize and maintain.
Compass is a tool to work with Sass and made it more easy and funnier to use.
This is a quick guide about how to install compass in Debian.
Here are the commands that you must run
sudo gem install sass
sudo gem install compass
sudo gem install sassy-buttons
For Theme Development in Drupal based on Omega Theme, you’ll need this
gem install compass-rgbapng
gem install toolkit
gem install susy