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.

The interpretation by the browser’s rendering engine is where your headaches begin. The W3C has gone to great lengths to create specifications by which browser developers should render the Web code. Nonetheless, bugs, omissions, and misinterpretations still creep in, meaning that no two browsers will render a Web page in exactly the same way. For the most part, these differences go unnoticed by most users, but occasionally the differences are glaring and require that you do some extra work to get the page to look right with the broadest spectrum of browsers.

Types of CSS Rules The best thing about cascading style sheets is that they are amazingly simple to set up. They don’t require plug-ins or fancy software—just text files with rules in them. A CSS rule defines what the HTML should look like and how it should behave in the browser window. CSS rules come in three types, each with specific uses: -HTML selector. The text portion of an HTML tag is called the selector. For example, h1 is the selector for the tag. The HTML selector is used in a CSS rule to redefine how the tag displays. -Class.