Be very careful what you show the client. They enable the web designer to create text styles with characteristics such as font, size, and color. Cascading Style Sheets are style definitions that can revise the style of an existing tag, or define a new style that can be applied to other tags, with complete control over text format. A style sheet can be inside a web page, or it can be an external file which all the pages in a web site link to. This linking is very powerful, because it enables the web designer to revise the external style sheet and see the changes automatically reflected across the entire site.
Styles Sheets can redefine existing tags.
Style Sheets can define new styles which can be applied to any text selection. Many of the styles defined in the CSS1 specification are not displayed properly inside Dreamweaver, and must be viewed in Netscape or Explorer. And of course, several of the style attributes display differently in Netscape and Explorer, or do not display at all in any browser. More information about each of these Style Definitions is available in the Dreamweaver Help. If you've modified a standard HTML tag with a new style, the style will automatically apply, and there is nothing to do beyond setting that tag in the normal way.