title: :nth-child related only to specific class or element
body: <p>it's possible assign :nth-child only to specific element, without count other element in the middle (ex <a href="http://jsfiddle.net/MgC4v/" rel="nofollow">http://jsfiddle.net/MgC4v/</a> with &lt;*br>).</p>
  
  <pre><code>&lt;p&gt;1&lt;/p&gt;
  &lt;br&gt;
  &lt;p&gt;2&lt;/p&gt;
  &lt;p&gt;3&lt;/p&gt;
  
  p:nth-child(3) {
      background-color:red;
  }
  </code></pre>
  
  <p>the red line is the second one, not the third..thanks</p>