An Introduction to Cascading Style Sheets (CSS)

This introduction isn’t meant to teach you everything about Cascading Style Sheets, but is rather meant as an overview of what can be done with CSS. Read through this article, and then decide whether or not CSS is right for your site. At the very least, you’ll know what can be done using CSS, so when the time comes to gain more control over the layout and typography of your site, you’ll know where to turn.

What Are Cascading Style Sheets?

CSS is a form of HTML mark-up that provides web designers with greater control over typography and spacing between elements on a page.

Why Should I Bother Using CSS?

1. Greater control over layout and typography. CSS provides you as a designer with precise control over the fonts used on your site, including size, letter spacing and text decoration. Elements on a page can be positioned precisely using CSS. In fact at least one major HTML Editor, Dreamweaver 2, uses CSS to control the layout of a page, although it does provide the option to convert to tables.
2. Site-wide changes become easy. Rather than having a style sheet as part of the HTML code of a page, it is possible to specify the URL of a style-sheet that is to be used when formatting a particular page. This makes it very easy to modify the entire site by simply editing a single file.

What About Browser Compatibility?

CSS support is provided in Internet Explorer 4+ and Netscape Navigator 4+. However, some annoying browser inconsistencies continue to make life difficult for those deciding to use CSS on their site. It is possible with a little bit of JavaScript to serve up different style-sheets depending on the browser that is being used to view your site. Alternatively, workarounds can be used so that the style-sheet works in both browsers correctly.

Source : SitePoint