Vertical divider line in a scrollable flexbox div element
<p>I have a vertically central adaptable scrollable flexbox element, which itself should have two columns (I solved this with two child-divs). The central flexbox should have a frame and a central divider line. </p>

<p>I can't get the central divider line to run all the way to the bottom of the scrollable flexbox. I tried it with a third child div element but the line only appears for the vertical extent of the flexbox. </p>

<p>How can I make two columns in a scrollable flexbox with a frame and central divider line running all the way to the bottom?</p>

<p>Thank you for your help.</p>

<p>Here is the example:
<a href="https://jsfiddle.net/soliman/0d0tn22x/2/" rel="nofollow">https://jsfiddle.net/soliman/0d0tn22x/2/</a></p>

<pre><code>&lt;body&gt;
  &lt;div class="wrapper"&gt;
    &lt;div class="header"&gt;
      &lt;h1&gt;Header&lt;/h1&gt;
    &lt;/div&gt;

    &lt;div class="content"&gt;

      &lt;div class="leftContent"&gt; Column 1
        With a lot of lines.
      &lt;/div&gt;

      &lt;div class="divider"&gt;&lt;/div&gt;

      &lt;div class="rightContent"&gt; Column 2
        With fewer lines
      &lt;/div&gt;
    &lt;/div&gt;

    &lt;div class="footer"&gt;
      Footer
    &lt;/div&gt;
  &lt;/div&gt;
&lt;/body&gt;
</code></pre>

<p>CSS:</p>

<pre><code>html,
body {
  height: 100%;
  margin: 0;
  padding: 0;
  background: black;
  color: red;
}

.wrapper {
  display: flex;
  /* use the flex model */
  height: 100%;
  flex-direction: column;
}

.header {
  margin: 1em 1em 0 1em;
}

.content {
  flex: 1 1 auto;
  display: flex;
  overflow-y: auto;
  position: relative;
  min-height: 100px;
  margin: 0 1em 0 1em;
  border: 6px double red;
}

.content &gt; div {
  width: 50%;
  padding: 3%;
}

.content &gt; div:first-child {
  margin-right: 10px;
}

.footer {
  margin: 0 1em 1em 1em;
}

.divider {
  position: absolute;
  left: 50%;
  top: 0%;
  bottom: 0%;
  border-left: 6px double red;
}
</code></pre>