Pay Attention to the CSS @media Rule: When to Define the Screen Media Type
http://www.ibm.com/developerworks/web/library/wa-media/index.html?S_TACT=105AGX08&S_CMP=EDU

Mertz, David
IBM
2007

Abstract:

The CSS @media rule is a useful way to target an HTML or XML document to an intended output device. Use of the print media is now fairly widespread, and provides a much cleaner means of creating printer-friendly pages than does a separate 'printable version.' The use of the screen media has been somewhat underused, perhaps because of an overly general assumption that screen is merely the 'default rendering.' However, in regard to positioning--especially absolute positioning--the screen media type has an important meaning that is not covered by media-free stylesheet rules.