Style sheets give your Web pages a unified look and feel.
When you work with style sheets, you refer to each element by its unique identifier, called a selector. The selector is simply the markup tag for the element without the first and last characters (<>).
When you want to apply a style definition to multiple elements, you can use a style class. After you create the style class, you can apply the class to any element in your Web page.
The best way to apply style definitions to multiple pages is to use a linked style sheet. With linked style sheets, you store the style definitions in separate files and reference the style sheet file in the pages that should use them.
When they are no longer required, you can remove style sheet definitions from Web pages quickly and easily.