Depending on the purpose for which you are using a Mathematica notebook, you may want to change its overall appearance. The front end allows you to specify independently the styles to be used for display on the screen and for printing. Typically you can do this by choosing appropriate items in the Format menu.
|ScreenStyleEnvironment||styles to be used for screen display|
|PrintingStyleEnvironment||styles to be used for printed output|
|Working||standard style definitions for screen display|
|Presentation||style definitions for presentations|
|SlideShow||style definitions for displaying presentation slides|
|Printout||style definitions for printed output|