title: Why does transition property not work with top/bottom/left/right set to "auto" on position absolute?
body: <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>.category  {
      width:150px;
      height:150px;
      border-radius:50%;
      margin: 20px;
      background-color: #f1f1f1;
      line-height:150px;
      text-align: center;
      cursor: pointer;
      font-size: 20px;
      position: relative;
  
  }
  
  .four span {
      background-color: #ddd;
      line-height:17px;
      position: absolute;
      top:100%;
      left:0;
      right:0;
      padding:20px;
      transition: 1s;
  }
  
  .four:hover span {
      bottom:0;
      top:auto;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>   
     
     
     &lt;div class="category four"&gt;&lt;span&gt;FOUR&lt;/span&gt;&lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>
  <p>As this example demonstrates, the <code>transition</code> does not work with the <code>auto</code> value set on the <code>top</code> direction.</p>
  <p>Can anybody explain why?</p>
  <p><strong>Note</strong>: You have to hover over the circle.</p>