JSFiddle - React, Tailwind, and code Playground

HTML

<div id="main-content">
    <div id="left-column"></div>
    <div id="right-column"></div>
</div>

CSS

#left-column {
    width: 100px;
    height: 200px;
    background-color: #f00;
    float: left;
}
#right-column {
    margin-left: 50px;
    width: 300px;
    height: 200px;
    float: right;
    background-color: #666;
}
#main-content {
    width: 450px;
    height: auto;
    background-color: #333333;
}