CSS

CSS stands for Cascading Style Sheets. CSS is a tool used to control the style of a web document. It controls the presentation and sometimes the layout of your web pages. Using CSS allows you to preset what styles will be used is certain areas of your web pages (font faces, colors, text sizes, etc).

For example, you can specify what font headlines will be vs. paragraph text or even link text. CSS lays out the rules for how things will appear on your site so that you don't have to specify it within the HTML coding in each and every section of your site. CSS allows for faster downloads, streamlined site maintenance, and the ability to affect the look of multiple pages of your site by editing one file.