title: Possible to make div's background in front of its ::after/::before pseudo element's one?
body: <p>I know there's a pic about pseudo elements' own relationship.</p>
  
  <p><a href="https://i.stack.imgur.com/MzWBj.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/MzWBj.jpg" alt="pseudo elements relationship, content&gt;::after&gt;::before&gt;element"></a></p>
  
  <p>(from <a href="https://css-tricks.com/pseudo-element-roundup/" rel="nofollow noreferrer">CSS tricks</a>)</p>
  
  <p>I met a problem about this, where I'd like to make <code>.nav-box</code>'s white background-color in front of <code>.nav-box::after</code>'s black one, as a floating menu list. Though I'd seen <a href="https://stackoverflow.com/a/9072467/4860812">this from previous question</a>, it seems to be impossible to make the above work. Would like to check if so.</p>
  
  <p>Code is also on <a href="http://jsbin.com/jedihi/edit?html,css,output" rel="nofollow noreferrer">JSBIN</a>.</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="false" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>body {
    position: relative;
    z-index: 1;
  }
  
  .nav-box {
      position: relative;
      z-index: 50; /* no effects */
      top: 0;
      right: 0;
      width: 60vw;
      height: 100vh;
      border: 1px solid red;
      background-color: white;
  }
  
  .nav-box::after {
      position: absolute;
      z-index: -1;
      content:"";
      top: 0;
      left: 0;
      width: 100vw;
      height: 100vh;
      background-color: black;
  }
  
  .nav-box::before {
    /* this will be a menu button */
      position: absolute;
      z-index: 10;
      right: 0;
      content: "O";
      color: orange;
      font-size: 40px;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;body&gt;
  &lt;nav class="nav-box"&gt;
    &lt;ul class="menu-box"&gt;
      &lt;li&gt;&lt;a href=""&gt;About&lt;/a&gt;&lt;/li&gt;
      &lt;li&gt;&lt;a href=""&gt;Blog&lt;/a&gt;&lt;/li&gt;
      &lt;li&gt;&lt;a href=""&gt;Contact&lt;/a&gt;&lt;/li&gt;
    &lt;/ul&gt;
  &lt;/nav&gt;
  &lt;/body&gt;</code></pre>
  </div>
  </div>
  </p>