Style sheets also reduce the need for multi-file search and replace; if an author decides to change the indentation of all paragraphs on a site, he or she only has to change one line on a style sheet.

This is an example of applying styles locally

Style sheets represent an enormous step forward for the Web. With the separation of content and presentation between HTML and style sheets, the Web no longer needs to drift away from the strong ideal of platform independence that provided the medium with its initial push of popularity. Authors can finally influence the presentation of documents without leaving pages unreadable to users.

The number of browsers supporting Cascading Style Sheets continues to increase rapidly. Netscape Navigator 4.7 features a large amount of support for CSS1 and CSS Positioning and has promised complete support in the upcoming version 5. Microsoft Internet Explorer 5 has partial CSS1 support with a strong level of CSS1 and CSS Positioning implemented in IE4, accompanied by early support for CSS Printing. According to The Web Standards Project the browser that correctly interprets the most CSS is Opera, a new lean, fast browser from Norway. You can get more information about Opera at www.opera.com. Style sheet support on the UNIX platform has long existed with Emacs-W3 and Arena, and the W3C's Amaya browser combines CSS support with a "WYSIWYG" editor for making CSS-enhanced Web pages.

For an overview of the CSS Specification http://webreview.com/wr/pub/guides/style/glossary.html