If you're familiar with Cascading Style Sheets (CSS), you've probably experienced the frustration of repeating selectors and duplicate color definitions. Less blends a programming language and CSS. It offers concepts like reusable variables and object-oriented mix-ins. If you're worried about learning another new technology, don't be. Less is super simple. Soon you'll be able to brag to your friends about your knowledge of Less! You can read up on what's available in Less at http://lesscss.org/. NoteA Hint About Less FilesYou'll notice that some Less files are prepended with an underscore (e.g., _print.less). That underscore helps to identify Less files that are not directly compiled into related .css files but are instead used as imports to other Less files. For instance, the _print.less file is never compiled into a _print.css file. Instead, its contents are imported (appended) to the theme.less file which is compiled into theme.css.