JSFiddle - React, Tailwind, and code Playground

HTML

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

CSS

.container {
    position:relative;
}

.left {
    position:absolute;
    left:0;
    right:250px;
    min-height: 50px;
    overflow: auto;
    border:1px dashed red;
}

.right {
    position:absolute;
    right:0;
    width: 250px;
    text-align: right;
    min-height: 50px;
    height: 100%;
    overflow: auto;
    border:1px dashed blue;
}