JSFiddle - React, Tailwind, and code Playground

HTML

<div id="wrapper">
    <div id="left">Content here<br>With another line</div>
    <div id="right">This div's height changes!</div>
</div>

CSS

#wrapper {
    height: 500px;
    width: 100%;
}
#left {
    background: green;
    width: 200px;
    display: table-cell;
}
#right {
    background: red;
    width: 200px;
    display: table-cell;
}