JSFiddle - React, Tailwind, and code Playground

HTML

<div class="top">
    <div class="left">Left</div>
    <div class="right">Right</div>
</div>

<div class="bot">
    <div class="left">Left</div>
    <div class="right">Right</div>
</div>

CSS

html, body {
    height: 100%;
}

.top, .bot {
    height: 50%;
}

.top {
    background-color: #369;
}

.bot {
    background-color: #963;
}

.left, .right {
    height: 100%;
    width: 50%;
    max-width: 800px;
    display: inline-block;
}

.left {
    background-color: rgba(0,0,0,.5);
    float: left;
}

.right {
    float: right;
}