title: Fixed position mask not working in firefox
body: <p>So I have a series of section tags all with position relative. Within those tags I have some images and text set with position fixed. In most browsers this creates a nice masking effect. However in fire fox things are stacked on top of each other and the effect just isn't working.</p>
  
  <p>Here is fiddle for reference = <a href="http://jsfiddle.net/LmkwxkfL/38/" rel="nofollow">http://jsfiddle.net/LmkwxkfL/38/</a> </p>
  
  <p>My sections</p>
  
  <pre><code>section{
      padding:20px;
      overflow:hidden;
      position:relative;
  }
  </code></pre>
  
  <p>My imgs </p>
  
  <pre><code>.billboard-img {
    width:100%;
    top: 0px;
    left:0px;
    z-index: -1;
    position: fixed;
  }
  </code></pre>
  
  <p>Again the above is working in chrome and safari but not in FF. Any help would be great.</p>