title: CSS z-index not working (position absolute)
body: <p>I am trying to make the black <code>div</code> (relative) above the second yellow one (absolute). The black <code>div</code>'s parent has a position absolute, too.</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>#relative {
   position: relative;
   width: 40px;
   height: 100px;
   background: #000;
   z-index: 1;
   margin-top: 30px;
  }
  .absolute {
   position: absolute;
   top: 0; left: 0;
   width: 200px;
   height: 50px;
   background: yellow;
   z-index: 0;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="absolute"&gt;
      &lt;div id="relative"&gt;&lt;/div&gt;
  &lt;/div&gt;
  &lt;div class="absolute" style="top: 54px"&gt;&lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>Expected Result:</p>
  
  <p><a href="https://i.stack.imgur.com/gXSAS.png" rel="noreferrer"><img src="https://i.stack.imgur.com/gXSAS.png" alt="enter image description here"></a></p>