title: CSS line-through is not disabled on nested span
body: <p>CSS :</p>
  
  <pre><code>ol {
      margin: 0 30px;
  }
      li {
          margin: 15px 0;
      }
      li.done {
          text-decoration: line-through;
      }
      li.done span {
          text-decoration: none;
          background: #ff0;
      }
  </code></pre>
  
  <p>HTML :</p>
  
  <pre><code>&lt;ol&gt;
      &lt;li class="done"&gt;Hello &lt;span&gt;World&lt;/span&gt;&lt;/li&gt;
      &lt;li&gt;World&lt;/li&gt;
  &lt;/ol&gt;
  </code></pre>
  
  <p>JSFiddle Demo : <a href="http://jsfiddle.net/pZye7/5/" rel="nofollow">http://jsfiddle.net/pZye7/5/</a> . And something weird on JSFiddle, ordered list's numbers are not displayed.</p>
  
  <p>My requirement : the word "World" should not have the line-through on it.</p>