JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrap">
    <div class="floatleft"></div>
    <div class="floatright"></div>
</div>

CSS

.wrap {
width: 100%;
}

.floatleft, .floatright {
    float:left;
    width: 80%;
    background-color: #ff0000;
    height: 400px;
}

.floatright {
    background-color: #00ff00;
    width: 20%;
}