Style With Substance

Making CSS Work

Eric A. Meyer

Standards Evangelist
Netscape Communications

The advantages

• Powerful set of capabilities hampered only by browser support
• Well-supported in current browsers
• Human-readable and -writable code for presentation
• Allows document structure to be very simple
• Reduces page weight
• Permits centralized changes to presentation of an entire site

(Re)stating some truths

• CSS is NOT a pixel-fidelity presentation language!
• Look for patterns in your structure
• Use actual (x)HTML elements; don’t try to make everything into divs and spans
• Tables are fine, but use them sparingly
• Write CSS that’s readable to you

A few basic terms

• selector, declaration, declaration block, rule

  h1 {color: red; background: yellow;}

• content-area
• element

  h1

• attribute

  bgcolor

• embedded stylesheet

  <style="text/css">...</style>

• external stylesheet

  <link rel="stylesheet" type="text/css"
     href="site.css">
  @import url(page.css);

Working with tables

• Tables are not evil, but they have been badly used and introduced a lot of wasted effort
• Non-table layout is possible in v5+ browsers, but it’s not always desirable
• If you’re going to use tables, strip them down to the bare minimum!
• Tables are most useful as layout-framing devices
• Add class and id hooks to cells in order to write styles that target cell contents
• Make use of contextual selectors to target contents

Floating

• Floating element is often a reasonable alternative to both tables and positioning
• Works well for simple two-column layouts and similar approaches
• Generally requires widths be set explicitly
• Best to leave most content in the normal flow and open space with margins or padding
• Structures are often the same as in positioning

Positioning

• A field to be trod lightly
• Push positioning too far, and it will break down
• Even with what we have, there's still a lot of room for interesting work
• Relative positioning is reliable
• Absolute positioning is fairly reliable
• Fixed positioning is unreliable, but can be fixed corrected

• http://and.doxdesk.com/software/

Fixed vs. liquid

• You can go whichever way you like, but...
• Fixed positioning is by its nature inflexible
• Liquid positioning adapts to the environment
• Too much flexibility can be disastrous, of course; thus min-width, max-width, and the height-based equivalents
• IE/Win can be made to support these properties

• http://and.doxdesk.com/software/

The legacy concern

• Older browsers like IE3 and NN4.x won't take well to any but the most basic positioning
• It's possible to mangle the page, or crash the browser, if it's pushed too far
• If this is a major concern you have a couple of choices
• One, use tables and don't worry about positioning
• Two, don't hand over the advanced styles to older browsers

Moving on

• When is it time to drop a browser?
• Simple: when your access logs (and your culture) say that you can
• It's important to define what "moving on" and "still functional" mean
• Consider establishing a support matrix
• Browser detection or style hiding may be a viable approach
• There is no universal answer, any more than a single cirriculum can satisfy the needs of every course in every department on every campus

Browser compatibility

• Really good or really bad, depending on what you’re interested in doing and where
• Between v5+ browsers, CSS1 support is excellent!
• Between v5+ browsers, CSS2 support is limited but fairly good
• Between v4 browsers, general CSS support is terrible
• IE6 is basically IE5 with a few changes
• The danger of designing for IE/PC is that IE lets you get away with stuff that isn’t correct, so VALIDATE!

• http://www.webreview.com/style/mastergrid.html
• http://www.westciv.com/style_master/academy/browser_support/index.html
• http://validator.w3.org/
• http://jigsaw.w3.org/css-validator/

DOCTYPE switching

• The DOCTYPE can have an effect on layout in IE6/Win IE5/Mac, Mozilla
• You get your choice of "quirks" and "standards" modes
• Behavioral differences are not consistent between browsers, but browsers are most consistent when in "standards" mode
• IE/Win will handle width differently between the two modes

• http://www.meyerweb.com/eric/dom/dtype/dtype-grid.html
• http://msdn.microsoft.com/library/en-us/dnie60/html/cssenhancements.asp
• http://www.people.fas.harvard.edu/~dbaron/mozilla/doctypes/

Hiding CSS

• You can hide CSS from older browsers, thus giving them the content and a less styled page without actually breaking anything
• These serve as feature-based detection without requiring Javascript
• @import is most widely used, but the voice-family hack is gaining in popularity
• A classic example is hiding box properties set on links, and hover styles, from NN4.x
• You can also use "overlapping" styles to strike a balance between NN4.x and recent browsers

• http://pixels.pixelpark.com/~koch/hide_css_from_browsers/
• http://pixels.pixelpark.com/~koch/hide_css_from_browsers/summary/

Core principles

• VALIDATE!
• Remember that your design is at the mercy of the user’s environment
• Author in the manner that works best for you
• Stick to simple stuff first, and build up complexity over time
• Try to think of page elements in a visual way, and visualize how your styles will affect their presentation
• Know the rendering mode your page will trigger
• Consider hiding advanced styles from older browsers

Far horizons

• We aren’t even completely sure what CSS makes possible
• Browser flaws held us back for a long time, but with recent releases the floodgates are opening
• New techniques and ideas are being uncovered even today
• Some Javascript-based fixes exist for legacy flaws!

• http://www.meyerweb.com/eric/css/edge/
• http://and.doxdesk.com/software/

Places to learn more

• http://www.w3.org/Style/CSS/
• http://two.pairlist.net/mailman/listinfo/css-discuss/
• http://www.meyerweb.com/eric/css/
• http://www.webreview.com/
• http://www.alistapart.com/
• http://www.htmlhelp.com/