Book HomeCascading Style Sheets: The Definitive GuideSearch this book Thursday 24th of July 2014 06:42:03 AM

Preface

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 whole story: the borders around an element are also considered to bepart of its foreground. Thus, there are two ways to directly affectthe foreground color of an element: by using thecolor property and by setting the border colorsusing one of a number of border properties. Primarily there is theborder-color property, as well as shorthandproperties such as border-top,border-right, border-bottom ,border-left, and border.

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.

Italic

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

TIP

indicates a note or tip relating to the nearby text.

WARNING

indicates a warning.



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Combined with vertical-align, even stranger things will happen. Figure 4-60 shows but one of these oddities. Since the SUP element has no decoration of its own, but it is elevated within an overlined element, the overline cuts through the middle of the SUP element:

P {text-decoration: overline; font-size: 12pt;}
SUP {vertical-align: 50%; font-size: 12pt;}