Steph,

The browser need to know when you want to view the document on screen and when you want to print it. To spcefiically tell the browser to load the print.css or print css selectors, you can follow the below example:

1. To embed the media type in an HTML document, we need to tell which file should be loaded in conjunction with the media type, for example:
   
   <link rel="stylesheet" href="skin.css" media="screen" />
   <link rel="stylesheet" href="print.css" media="print" />
   
   However, by default the document will load with skin.css, media declaration like media="screen" can be omitted. 
2. To embed the media type in a CSS selector (in the same CSS document, skin.css for example), you can do this:
   
   .my_styles {background: gray;}
   
   @media print {
   
       .my_style {background: white;}
   
     }

You can take the same approach to hide the menu in your print document.

Hope this helps!

Cuong Dang
Co-founder: Enliven, dnnGallery
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I'm the author of DNN and Web Standards Wrox Blox