title: Difference size font rendering on Windows VS MacOS. How to solve?
body: <p>I've been wondering myself why on windows my font looks smaller, and much crappier than on OSX.</p>
  
  <p>Screenshot Mac VS Windows : <a href="http://screencast.com/t/UUxqLRhM" rel="nofollow">http://screencast.com/t/UUxqLRhM</a></p>
  
  <p>Is that because i used "em" on some rules instead of "px" ?</p>
  
  <p>Thanks.</p>