Cascading style sheets

You use cascading style sheets to control the layout and appearance of your topic text and elements. These style sheets allow you to define a full array of layout specifications for HTML topics such as font style and size, line spacing, paragraph indents, and more. Similar to templates used by Microsoft Word and other programs, a style sheet is a template that controls the formatting of HTML Help topics. You can alter the appearance of an HTML Help topic by changing the formatting assigned to it from a style sheet.

There are three ways to work with style sheets and styles:

Cascading style sheets is the term for HTML styles developed by the World Wide Web Consortium (W3C). "Cascading" refers to the hierarchy of the three styles (external style sheets, embedded, inline), when they are used in combination.