Ruby rails: stylesheets

Stylesheets change colours, fonts, and general style of rendered html.
Rails uses sass to render stylesheets.

Locations

{project}/app/stylesheets/application.scss	sass file for entire application (if no more specific css is found)
{project}/app/stylesheets/{controller}.scss	sass file for view
http://localhost:3000/assets/{controller}.css	preview of CSS rendered by sass (blank page if no css defined!)