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="container d-flex h-100 flex-column">
    <div class="row flex-fill d-flex">
      <div class="col-8 bg-dark m-2">
        TEXT
      </div>
      <div class="col bg-dark m-2">
        TEXT
      </div>
    </div>
    <div class="row flex-fill d-flex">
      <div class="col bg-dark m-2">
        TEXT
      </div>
    </div>
  </div>

CSS

html, body {
  height: 100%;
}

.flex-fill {
  flex: 1;
}

.container {
  padding: 2em 1em;
}