JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//code.jquery.com/jquery-3.3.1.slim.min.js"></script>
<link rel="stylesheet" href="//stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css">
<script src="//cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.0/umd/popper.min.js"></script>
<script src="//stackpath.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">
<div class="root">
  <div class="container flex-section">
    <div class="flex-no-shrink">
      <h1>test</h1>
      <p>
      more stuff
      </p>
    </div>
    <div class="row">
      <div class="col col-6 flex-col-scroll" style="background-color: pink;">
        <h3>Column 1</h3>
        <p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>end line</p>
      </div>
      <div class="col col-6 flex-col-scroll" style="background-color: lightblue;">
        <h3>Column 2</h3>
        <p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>new line</p><p>end line</p>
      </div>
    </div>
  </div>
</div>

CSS

html, body {
  height: 100%;
}

.root {
  display: flex;
  flex-direction: column;
  height: 100%;
}

.flex-section {
  flex-grow: 1;
  display: flex;
  flex-direction: column;
  min-height: 0;
}

.flex-col-scroll {
  flex-grow: 1;
  overflow: auto;
  min-height: 100%;      
}

.flex-no-shrink {
  flex-shrink: 0;
}