CSS Highlights
Assuming that you’ve marked up the structure of your document with many well-meaning elements, we’ll now turn to CSS to transform your well-organized outline into a multicolumned, colorful beauty. However, this is just the tip of the iceberg; of course, we focus on issues related to universal design. If you are new to CSS, check out a comprehensive CSS reference (anything by Eric Meyer or Christopher Schmitt).
Liquid Layout
One of the first concepts to introduce is units of measure, as they are a key component in designing a liquid layout. Early web designers were making the transition from print design to the Web. In print, you have fixed layouts that are precisely defined and static—they are “pixel-perfect.” But those designers had no control over which browser someone used, or the size of the browser window, or the size of the text, which meant that their pixel-perfect designs weren’t very perfect.
As HTML and CSS evolved, designers realized they could create designs that would reflow to accommodate browser version, window size, and text characteristics. Instead of seeing everything as absolutely positioned, designers started thinking in terms of relative positions.
Thus, there are three ways to specify length: relative units, absolute units, and percentages. Here are the definitions from the CSS2.1 specification:[17]
Relative length units specify a length relative to another length property. Style sheets that use relative units will more easily scale from one medium ... |