Style Sheets work in 4.0 and later browsers. Internet Explorer 3.0 recognizes some style attributes, but most earlier browsers ignore them. When you create a style for the H1 tag, all the text with the H1 tag immediately changes. Custom styles are similar to the styles you use in a word processor, except that there is no distinction between character and paragraph styles. You can apply custom styles to any range or block of text.
Text formatting that is manually applied to ranges of text can take precedence over styles.
To make styles control the formatting for a paragraph, remove all other formatting settings. Although you can set all the style attributes defined by the CSS1 specification in Dreamweaver, not all attributes appear in the Document window. It is also important to note that some of the CSS style attributes that you can set with Dreamweaver appear differently in Microsoft Internet Explorer 4.0 and Netscape Navigator 4.0, and some are not currently supported by any browser. When you apply two or more CSS styles to the same text, the styles may conflict and produce unexpected results. For example, one style may specify green as the text color and the other style may specify purple.