Doing It In Style:
CSS (Cascading Style Sheets)

Cascading style sheets are part of the standards promoted by the World Wide Web Consortium (W3C). They have been widely hailed as a return to the basic HTML separation of structure and presentation, as well as a method promoting rapid content development. Both these claims are true and are eminently applicable to online Help.

Cascading style sheets (CSS) define the look of an HTML Help system’s look and feel—and they do it more quickly and efficiently than would be otherwise possible. A good cascading style sheet can change the design of hundreds of HTML pages with the modification of a single line in a simple text file. This speed and efficiency is particularly important in online Help systems, where rapid change appears to be the most enduring fact of professional life.

In addition, CSS gives you control over the appearance of the finished product which is otherwise difficult to achieve in HTML. In very uncomplicated terms, cascading style sheets are simple text files that specify the formatting (font, line spacing, indents, etc.) for each element (such as level 1 headings or list items) on an HTML page.

This chapter discusses cascading style sheets: what they are, how to use them, and how to create them. Since CSS, like any computer-based standard, has many different implementations, this chapter focuses on how CSS standards apply to HTML Help and, even more specifically, to compiled HTML Help. In general, this means following Microsoft’s implementation of CSS in Internet Explorer versions 4 and above. Fortunately, Microsoft and the major browsers seem to be moving towards ever greater adherence to the W3C recommendations, so that Help writers will find it ever easier to create a single cascading style sheet applicable to most user situations.