title: IE8 incompatibility of z-index and body:after
body: <p>I have a two-way gradient background and a navigation bar. All the browsers display right except IE8 (even IE7 is ok).</p>
  
  <p>The simplified code is here: <a href="http://jsfiddle.net/HKg9d/3/" rel="nofollow">http://jsfiddle.net/HKg9d/3/</a></p>
  
  <p>If you adjust the window size and let the square cross the two parts of the background, the bottom part will overlap the square, only in IE8.</p>