CSS (cascading stylesheets) is a simple mechanism for controlling the style of a Web document without compromising its structure. By separating visual design elements (fonts, colors, margins, and so on) from the structural logic of a Web page, CSS give Web designers the control they crave without sacrificing the integrity of the data - thus maintaining its usability in multiple environments. In addition, defining typographic design and page layout from within a single, distinct block of code - without having to resort to image maps, <font> tags, tables, and spacer GIFs - allows for faster downloads, streamlined site maintenance, and instantaneous global control of design attributes across multiple pages.

Client-side support for the various CSS properties is uneven, even among browsers that support stylesheets. The CSS properties and values presented here are those supported by both Microsoft Internet Explorer 4 and Netscape Navigator 4.