title: pseudo-element :first-child not being picked up
body: <p>Given the following snippet, I would expect the div containing "Award 1" to have a red background colour. Can someone explain to me why it does not? The first item should have a border top.</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>.item-wrap:first-child .item {
      border-top: 1px solid black;
  }
  
  .item {
      width: 100%;
      border-bottom: 1px solid black;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="row awards"&gt;
    &lt;div class="col-xs-12"&gt;
      &lt;h2 class="no-border"&gt;Awards&lt;/h2&gt; 
    &lt;/div&gt;
    &lt;div class="col-xs-12 item-wrap"&gt;
      &lt;div class="item"&gt;Award 1&lt;/div&gt;
    &lt;/div&gt;
    &lt;div class="col-xs-12 item-wrap"&gt;
      &lt;div class="item"&gt;Award 2&lt;/div&gt;
    &lt;/div&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>