You probably know that the CSS3 spec includes a number of structural pseudo-classes, some of which use parentheses. The purpose of the parentheses is to allow one or more elements to be selected based on a keyword (either odd or even), an integer, or an expression.
Tag: Pseudo Class
Designing with CSS3 Support & Alternative Fallbacks
Make the most of CSS3 by designing with the latest and greatest technology on browsers with CSS3 support while providing alternative fallbacks for browsers without CSS3 support.