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The subject of this book is, as you might have guessed by the cover, Cascading Style Sheets (CSS). There are two "levels" to CSS; these are referred to as CSS1 and CSS2. The difference between the two is that CSS2 is all of CSS1, plus a lot more. This book attempts to cover all of CSS1, and CSS positioning, which is a part of CSS2. The rest of CSS2 is excluded because, at the time of this writing, nobody had implemented most of it. Rather than cover a lot of theoretical territory, we chose to stick to what was currently usable.

If you are a web designer or document author interested in sophisticated page styling, improved accessibility, and saving time and effort, then this book is for you. All you really need before starting the book is a decent knowledge of HTML 4.0. The better you know HTML, of course, the better prepared you'll be. You will need to know very little else in order to follow this book.

It is important to remember something about web standards and books: the former are continually evolving, while the latter are frozen in time (until the next edition comes out, anyway). In the case of HTML and CSS, there are a great many changes afoot even as these words are being written. The recent formalization of XHTML 1.0 as a full W3C Recommendation, for example, is a major milestone in the evolution of the World Wide Web. There are likely to be even more levels to CSS, further extending the ability to style documents; major web browsers are approaching full CSS1 support, and robust CSS2 implementations can be seen lurking on the horizon. This is an exciting time to be a designer, and learning CSS now will give you a leg up on the future.

0.1. Typographical Conventions

The following typographical conventions are used in this book:

Constant width

is used to indicate code examples, HTML tags and CSS elements.

Constant width italic

is used for replaceables that appear in text.


This causes the bullet to be placed "inside" the list item's content. The exact way this happens is undefined, but Figure 7-86 shows one possibility.

Figure 7-86

Figure 7-86. Placing the bullets inside and outside list items

CSS2, by the way, provides a good deal more control over the positioning of the bullets (called "markers" in CSS2); again, this is discussed in Chapter 10, "CSS2: A Look Ahead".

is used to introduce new terms and to indicate URLs, filenames, and pathnames.


indicates a note or tip relating to the nearby text.


indicates a warning.

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available and will therefore use them.

11.2.4. Styling Common Elements

If you have documents in which there is a certain block ofcommon markup -- say, a table thatholds links to the main pages of your site -- it's easy toelement. Let's say you want to put 5-pixel borders around anyhyperlink:

A:link {border: 5px solid blue;}

If you don't set a large enough line-heightto accommodate the border, it will be in danger of overwriting otherlines, as shown in Figure 8-62.

Figure 8-62

Figure 8-62. Inline borders can be overlapped

One solution is to increase the line-height of the</P> <!-- ...or, to put it another way... --> <P> bold <SPAN> bold <STRONG> regular <B> regular <STRONG> regular </STRONG></B></STRONG></SPAN>. </P>

Ignoring the fact that this would be entirely counterintuitive, what we see in Figure 5-16 is that the main paragraph text has a weight of 900 and the SPAN aweight of