title: Use CSS3 transitions with gradient backgrounds
body: <p>I'm trying to transition on hover with css over a thumbnail so that on hover, the background gradient fades in. The transition isn't working, but if I simply change it to an <code>rgba()</code> value, it works fine. Are gradients not supported? I tried using an image too, it won't transition the image either.</p>
  
  <p>I know it's possible, as in another post someone did it, but I can't figure out how exactly. Any help> Here's some CSS to work with:</p>
  
  <pre class="lang-css prettyprint-override"><code>#container div a {
    -webkit-transition: background 0.2s linear;
    -moz-transition: background 0.2s linear;
    -o-transition: background 0.2s linear;
    transition: background 0.2s linear;
    position: absolute;
    width: 200px;
    height: 150px;
    border: 1px #000 solid;
    margin: 30px;
    z-index: 2
  }
  
  #container div a:hover {
    background: -webkit-gradient(radial, 100 75, 100, 100 75, 0, from(rgba(0, 0, 0, .7)), to(rgba(0, 0, 0, .4)))
  }
  </code></pre>