Cascading Style Sheet (CSS)

One of the W3c's major efforts at peace keeping was to develop Cascading Style Sheets (CSS), a system that separates the content of a page (written in HTML) from the format written in CSS and in so doing allows for more complete control over the design of a Web page while keeping the page universal. In addition, CSS can be applied to several pages at once, Helping the designer save time by storing all the formatting in one file.

That was the theory, anyway. In practice, neither the Microsoft or the Netscape, despite having participated in the development of CSS, has gotten around to fully implementing it in their browsers. In fact, the browser that best supports CSS is a newcomer to the battle: Opera, developed in Norway by a company whose chief technical officer is Hakon Lie, one of the major forces behind CSS at the W3C.

The lack of universal support for CSS has not discouraged designers from using it, however. CSS's powerful formatting and layout capabilities have attracted designers in much the same way that Netscape's extensions did in their day. With much the same problems pages that work only on some browsers and that completely break down in others..

But in todays browser I think almost all browser already supports CSS.
Elizabeth Castro HTML for the world wide web