JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
        <div id="left-column">
            left
        </div>
        <div id="main-column">
            main
        </div>
    </div>

CSS

#container {
            display: table;
            width: 100%;
            background-color: green;
        }
        #left-column {
            display: table-cell;
            min-width: 200px;
            width: 20%;
            background-color: red;
        }
        #main-column {
            display: table-cell;
            width: 80%;
            min-width: 400px;
            background-color: black;
            color: white;
        }