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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

with this approach, you can match a class attribute with a value of driving directions in this way:

Again, this probably seems a bit easier to type. So why go to all the effort of using the longer notation of attribute selectors? The reason to use attribute selectors is that the .class and #ID selectors apply only to HTML documents, or to any other document that uses a language that includes the concepts of class and ID. Other languages, such as

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 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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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 small changes made to the structure of each letter to account for the altered appearance. This is especially true of serif fonts, where in addition to the fact that the text characters "lean," the serifs may be altered in an italic face. Oblique text, on the other hand, is simply a slanted version of the normal, upright text. Font faces with labels like Italic, of this story will sound pretty familiar because it's largelythe same as what we discussed with margins and inline elements.

In the first place, no matter how thick you make your borders oninline elements, the line-height of the element won't change.Let's set top and bottom borders on boldfaced text:

B {border-top: 10px solid gray; border-bottom: 5px solid silver;}

Once more, this is allowed in the specification, but it will haveabsolutely no effect on the line height. However, since borders are shown in Figure 7-84.

Figure 7-84

Figure 7-84. Switching off image bullets in sublists

WARNING

Remember that this may not be true in the real world: a user agent may have already defined a list-style-type for UL UL, so the value of square won't be inherited after all. Your browser may vary.

Figure 8-41

Figure 8-41. Backgrounds "slide under" floated elements

Because the floated element is both within and without the flow, thissort of thing is bound to happen. What's going on? Well, thecontent of the paragraphs is being "displaced" by thefloated element. However, each paragraph's element width isstill as wide as its parent element. Therefore, its content areaspans the width of the parent, and so does the background. The actualcontent doesn't flow all the way across its own content area inorder to avoid being obscured behind the floating element.