Style sheets are groups of style rules, which in turn are groups of properties that define how an HTML element appears in a Web browser - e.g. Arial, italic and blue.

Styles can be defined either within an HTML document or in an external file that can linked to multiple pages (or even a whole site) making side-wide changes easy to implement.

Although style sheets use a different syntax to HTML, they're not particularly complicated to learn and designers will soon appreciate the extra control over page layout and text formatting offered, with the bonus of simplified coding and increased accessibility.

Although there's nothing to stop you using your favourite HTML editor to write CSS, I'd recommend getting a dedicated editor, with my recommendation being the excellent Topstyle cascading style sheet editor

Style sheets can also be used with JavaScript to create dynamic and powerful DHTML effects - check out coolhomepages.com for some stunning examples.

Although there are some irritating cross-browser incompatibilities that can drive web authors mad (see: CSS bugs and workarounds), it's definitely worth persevering with style sheets - check out the listing of online tutorials opposite to get you started!