JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wraper">
    <div class="left"></div>
    <div class="right"></div>
</div>

CSS

body {
    margin: 0;
    padding: 0;   
}

.wraper {
    margin: 0 10px;   
}

.left {
    width: 20%;
    height: 300px;
    margin-right: 10px;
    background: orange;
    float: left;   
}

.right {
    height: 300px;
    background: green;
    overflow: hidden;   
}