JSFiddle - React, Tailwind, and code Playground

HTML

<div id="left">
</div>
<div id="right">
</div>

CSS

#left{ 
    background: blue;
    display: block;
    float: left;
    height: 1800px;
    width: 100px;
}

#right{ 
    background: red;
    float: right;
    height: 1800px;
    width: 150px;
}