JSFiddle - React, Tailwind, and code Playground

HTML

<div id="wrapper">
	<div id="content">
	</div>
</div>

<footer></footer>

CSS

body {height: 100%;}

#wrapper {min-height: 100%; background: #999;}
#wrapper #content {padding-bottom: 140px;}

footer {height: 140px; margin-top: -140px; background: #333;}