Position element at the bottom with prior element filling up height
<p>First div should fill up remaining height that's left while second div should be positioned at the bottom with it's initial height.</p>

<p><strong>DEMO:</strong></p>

<p><div class="snippet" data-lang="js" data-hide="false">
<div class="snippet-code">
<pre class="snippet-code-css lang-css prettyprint-override"><code>.container {
  width: 240px;
  height: 400px;
  background: #E0E0E0;
  display: flex;
  flex-direction: column;
}

.first {
  border :1px solid black;
  padding: 1em;
  box-sizing: border-box;
}

.second {
  border: 1px solid blue;
  padding: 1em;
  box-sizing: border-box;
}</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="container"&gt;
&lt;div class="first"&gt;
I SHOULD FILL WHATS REMAINING AFTER SECOND ONE
&lt;/div&gt;
&lt;div class="second"&gt;
&lt;div&gt;
I SHOULD BE AT THE BOTTOM FILLING ONLY MY OWN HEIGHT
&lt;/div&gt;

&lt;/div&gt;</code></pre>
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