title: CSS background color not working
body: <p>I set the background color of the outer div to blue but it is not displayed. Why?</p>
  
  <p>A demo of it:</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>.question-template {
      width: auto;
      height: auto;
      background-color: blue;
  }
  .question {
      float: left;
      margin: 10px;
  }
  .participants {
      background-color: green;
      float: left;
      margin: 10px;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;body&gt;
  &lt;div class="question-template"&gt;
      &lt;div class="participants"&gt;234&lt;/div&gt;
      &lt;div class="question"&gt;Some lorem ipsum text&lt;/div&gt;
  &lt;/div&gt;
  &lt;/body&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p><a href="http://jsfiddle.net/4zjtp/" rel="noreferrer">jsFiddle</a></p>