What's CSS?

Cascading Style Sheets (CSS)
Specifically, CSS allows you to style:
Text size, color, style, typeface, and alignment.
Link color and style.
Image size and alignment.
List bullet styles and indentation.
Table size, shading, borders, and alignment.

The advantages of using CSS?
The layout of a web page is better controlled.
Style (CSS) kept separate from structure (HTML), means smaller file size.
Reduced file size means reduced bandwidth, which means faster loading time.