Print CSS is a Cascading Style Sheet intended for print documents when users want to print the web page for reference. It applies to document view in print preview mode as well, therefore you can preview how the print document looks like after you have made amendment on your Print CSS.

Print CSS

Live Demo: Menu Bar -> File -> Print Preview or Alt + F then V.
View Full Print StyleSheet

To show main source of content:
http://www.onextrapixel.com/2009/05/05/how-to-create-a-simple-print-css-for-your-site/