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Appendix A. CSS Resources

Contents:

General Information
Tips, Pointers, and Other Practical Advice
Online Communities
Bug Reporting

There are a number of very good CSS-related resources available on the Web. Here are some of them.

A.1. General Information

These resources provide a good overview of what's happening in the world of CSS or otherwise provide you with a broad look at CSS.

A.1.1. CSS Recommendations

http://www.w3.org/TR/REC-CSS1

http://www.w3.org/TR/REC-CSS2

When all else fails, you can always use the source, Luke. The specifications contain, albeit in a somewhat terse and not always easily decipherable form, the complete description of how conforming user agents should handle CSS. They also contain a complete CSS parsing grammar and forward-compatible parsing rules, both of which are invaluable to the people who write user agents but of minimal interest to almost everyone else.

A.1.2. W3C CSS Activity Page

http://www.w3.org/Style/CSS

This is, officially speaking, the online center of the CSS universe. There are links to the CSS Recommendations, to new ideas under consideration, and to other sites about CSS. There are links to historical style sheet proposals, to information about current usage and implementations of CSS, and more. There are also lists of books about CSS, news of new CSS tools, and many other useful bits of information.

A.1.3. W3C CSS Test Suite

http://www.w3.org/Style/CSS/Test/

This presents a fairly complete set of pages designed to test any CSS implementation. Each page of the suite tests various aspects of CSS properties, one property per page. The tests were largely developed by the author of this book, Håkon Lie (Opera Software), and Tim Boland (NIST), with many contributions from the CSS community and even the browser vendors themselves. If you're wondering how good your browser is at handling CSS1, this is the place to find out. As of this writing, the Test Suite covers only CSS1, but a CSS2 Test Suite is expected in the near future.

A.1.4. Error Checkers

You can save a lot of time and effort simply by running your CSS through a validity checker. This is particularly recommended if you're thinking about asking for help online, because if your CSS contains errors, the first thing the experts will tell you to do is to use a validator. May as well get into the practice first.

A.1.4.1. W3C CSS Validator

http://jigsaw.w3.org/css-validator/

If you're having trouble getting your style sheets to work, it might be the result of a typographical error, or some other basic error that is difficult to diagnose. You could spend a long time combing through your styles, exhaustively checking each rule for correctness -- and that's a good exercise, of course -- but you could also have a program do it for you, and simply tell you if it found any errors. The W3C CSS Validator will do exactly that. You can supply it with the URL of a style sheet or document containing styles, or simply paste a block of styles into an input field, and let the validator tell you if your problems are the result of a misspelled color name (or something similar). The chief drawback, for most people, is the technical nature of its reporting. Unless you're already familiar with HTML and CSS, the results you get back may be somewhat confusing.

A.1.4.2. WDG CSScheck

http://www.htmlhelp.com/tools/csscheck/

Similar in nature to the W3C's validator, CSScheck offers much friendlier error messages, which makes it more useful to the

Still, font-style can be useful. For example, itis a common typographic convention that a block quote should beitalicized, but that any specially emphasized text within the quoteshould be upright. In order to employ this effect, shown in Figure 5-28, you would use these styles:

beginning author. In addition to indicating the severity of the error with whimsical icons (American-style traffic signals, at last check), CSScheck provides a message detailing each problem, as well as the reason it is a problem. It is possible to learn a great deal about good document authoring practices simply by running a few style sheets through CSScheck and carefully reading its responses.



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P.new1 {border-style: solid dashed none;}P.new2 {border-style: solid dashed none dashed;}
Figure 7-34

Figure 7-34. Equivalent style rules

In case you're wondering, under CSS1, there is no way todirectly set the style for only a single side using something likeborder-top-style, since no such property exists inCSS1 (although that property, and others like it, were introduced inCSS2). You can, however, sneak around this limitation by declaringthe style for a given border using one of the shorthand properties you have to be to shrink text in lists like that?" True,it's easy to spot this with lists. However, think about howmost of your pages are structured (with nested tables) and thenconsider this rule:

BODY {font-size: 12pt;}TD {font-size: 80%;}

All it takes is three levels of nesting in your tables, and you endup with 6-point text (12 x 0.8 x 0.8 x 0.8 =6.144). Many complicated pages have at least three levels of nesting,

At first glance, this seems no different than if the * were left out, instead relying on inheritance to carry the color to all descendants of DIV. However, there is a very real difference: the rule shown would match every DIV descendant, and therefore override the inheritance mechanism. Thus, even anchors (which are descendants of a DIV) would be made purple under the given rule, whereas simple inheritance would not be sufficient to make them purple.

Thatleaves only an explanation of the difference betweenitalic and oblique text. Forthat, it's easiest to turn to Figure 5-24,which illustrates the differences very clearly.

Figure 5-24

Figure 5-24. Italic and oblique text in detail

Basically, italic text is in some way its own font, with smallchanges made to the structure of each letter to account for thefont that has been declared to be italic may switch from being italic to oblique depending on the actual size of the font. The display of Times on a Macintosh, for example, is as shown in Figure 5-27, and the only difference there is a single point in size.

Figure 5-27

Figure 5-27. Same font, same style, different sizes

There isn't much that can be done about this, unfortunately, save better font handling by operating systems. Usually, the italic and oblique fonts look exactly the same in web browsers.