JSFiddle - React, Tailwind, and code Playground

HTML

<div class="a">foo<br>bar<br>foobar<br>fo<br>bar<br>foobar<br>foo<br>bar<br>foobar<br>foo<br>bar<br>foobar<br>foo<br>bar<br>foobar</div>
<div class="b">foo<br>bar<br>foobar</div>
<div class="c"></div>

CSS

.a {
    background-color: red;
    width: 50%;
    float: left;
}

.b {
    background-color: green;
    width: 50%;
    float: right;
}

.c {
    background-color: blue;
    height: 100px;
    clear: both;
}