JSFiddle - React, Tailwind, and code Playground

HTML

<div id="wrapper">
    <div id="left-column"></div>
    <div id="right-column"></div>
</div>
<div id="footer">
</div>

CSS

body, html {height:100%; padding:0; margin:0;}
#wrapper {height:100%; padding:0 0 60px 260px; box-sizing:border-box; -moz-box-sizing:border-box;}
#left-column {width:260px; margin-left:-260px; float:left; height:100%; background-color:red; overflow-y:scroll;}
#right-column {width:100%; float:left; height:100%; background-color:blue; overflow-y:scroll;}
#footer {height:60px; position:fixed; bottom:0; left:0; width:100%; background-color:green;}

JavaScript

fixed;