CSS level 2 (CSS2) The CSS2 spec came out in 1998 and is the most widely adopted by browser makers. Level 2 includes all the attributes of the previous two versions, plus an increased emphasis on international accessibility and the capability to specify media specific CSS. In 2006, the W3C published an updated version: CSS Level 2.1, which corrected some errors, clarified a few issues, and included specifications for features that had already been implemented in some browsers. CSS2.1 has effectively replaced CSS2.

CSS level 1 (CSS1) The W3C released the first official version of CSS in 1996. This early version included the core capabilities associated with CSS, such as the ability to format text, set fonts, and set margins. Netscape 4 and Internet Explorer 3 and 4 support Level 1. Web designers needed a way to position elements on the screen precisely. CSS1 was already released, and CSS Level 2 was still in the future, so the W3C released a stopgap solution: CSS-Positioning. This standard proposed that the parties concerned could debate for awhile before the CSS-P standard became official.

HTML is how Web pages are structured. CSS is how Web pages are designed. This book deals primarily with how to use CSS to add a visual layer to the HTML structure of your Web pages. CSS is a style sheet language; that is, it is not a programming language. Instead, it’s code that tells a device (usually a Web browser) how the content in a file should be displayed. CSS is meant to be easily understood by anyone, not just “computer people.” Its syntax is straightforward, basically consisting of rules that tell an element on the screen how it should appear.