title: Set child of flex element to be height of parent?
body: <p><a href="https://jsfiddle.net/8om6dxt6/" rel="nofollow noreferrer">JSFiddle</a></p>
  
  <p>I wish to have <code>a</code> to the left and <code>b</code> to the right. In the center is a list aligned horizontally. I want the <code>full-height</code> div to be the height of the parent.</p>
  
  <p>So:</p>
  
  <pre><code>a            1 2 3             b
  </code></pre>
  
  <p>Here's the HTML:</p>
  
  <pre><code>&lt;div class="container"&gt;
    &lt;div class="a"&gt;
      a
    &lt;/div&gt;
  
    &lt;div class="full-height"&gt;
        &lt;ul&gt;
            &lt;li&gt;1&lt;/li&gt;
            &lt;li&gt;2&lt;/li&gt;
            &lt;li&gt;3&lt;/li&gt;
       &lt;/ul&gt;
    &lt;/div&gt;
  
    &lt;div&gt;
        b
    &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>I've looked at other SO posts which have 2 solutions:</p>
  
  <ul>
  <li>Add <code>flex-direction: column;</code> to the parent. Which won't work in this situation as parent needs to be horizontally laid out.</li>
  <li>Set parent height and make child <code>height: 100%</code>. I need the parents height to be dynamic.</li>
  </ul>
  
  <p>Any ideas?</p>