Cascading Style Sheets (CSS) is a W3C standard mark-up language for defining the appearance of web pages. The use of CSS allows developers to fully separate the content of the page from its presentation, speeding up the development process and also making the pages load more quickly in the browser. Whereas 20th century websites typically used tables to construct web pages and position elements, CSS now provides a cleaner and more efficient way of controlling all aspects of web page layout.

Adobe Dreamweaver is a very widely used platform for developing web sites and web content and, although used by experienced developers, is also widely used by non-specialists for whom Dreamweaver’s user-friendly visual interface takes the pain out of web site creation. The way in which Dreamweaver implements CSS is very important for the casual user, since it will influence the kind of sites they end up producing.