title: how to size div to fit the remaining page content with flex
body: <p>I have the following markup:</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>.layout {
    display: flex;
    flex-direction: column;
    background-color: gray;
    height: 100vh;
  }
  
  .app-bar {
    background-color: lightblue;
  }
  
  .app-drawer {
    background-color: black;
    color: white;
    flex-grow: 1;
  }
  
  .app-sidebar-container {
    
    
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="layout"&gt;
    &lt;div id="app-bar-container"&gt;
      &lt;div class="app-bar"&gt;APP BAR&lt;/div&gt;
    &lt;/div&gt;
    &lt;div id="app-sidebar-container" class="app-sidebar-container"&gt;
      &lt;div class="app-drawer"&gt;DRAWER AND CONTENT&lt;/div&gt;
    &lt;/div&gt;
  &lt;/div</code></pre>
  </div>
  </div>
  </p>
  <p>How should I modify this in order to get the drawer and content black div to stretch the entire remaining layout element (gray)?</p>
  <p>Thanks.</p>