title: How extend bootstrap classes
body: <p>I am doing my first steps with Bootstrap Twitter, and need to extend components. 
  For example, I would like to change the navbar background, but without changing the original css file.</p>
  
  <p>I tried to create a new class <code>.test</code> with the new background:</p>
  
  <pre><code>.test{
      background-color: red !important;
  }
  </code></pre>
  
  <p>And I've invoked it in the hmtl as:</p>
  
  <pre><code> &lt;div class="navbar navbar-fixed-top test"&gt;
  </code></pre>
  
  <p>But, it doesn't work.
  How can do this?</p>