title: Excluding an element from nth-child pattern
body: <p>Let's say I have these elements:</p>
  
  <pre><code>&lt;li class="class1"&gt;content&lt;/li&gt;
  &lt;li class="class1"&gt;content&lt;/li&gt;
  &lt;li class="class1 class2"&gt;content&lt;/li&gt;
  &lt;li class="class1"&gt;content&lt;/li&gt;
  &lt;li class="class1"&gt;content&lt;/li&gt; &lt;!-- I want nth-child(4n) to select this--&gt;
  &lt;li class="class1"&gt;content&lt;/li&gt;
  &lt;li class="class1"&gt;content&lt;/li&gt;
  &lt;li class="class1"&gt;content&lt;/li&gt;
  </code></pre>
  
  <p>I want to use a <code>.class1:nth-child(4n)</code> to select every 4th element, but if an element has BOTH <code>class1</code> and <code>class2</code> I don't want it to be included in the "every 4th" counting--I just want it to be ignored.</p>
  
  <p>I've tried <code>.class1:not(.class2):nth-child(4n)</code>, but it doesn't seem to work. Any ideas?</p>
  
  <p>Here's a JSFiddle for experimentation: <a href="http://jsfiddle.net/jWxb6/2/" rel="nofollow">http://jsfiddle.net/jWxb6/2/</a></p>