JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrapper">
    <div class="a">asdfdsf<Br>dfdsf<Br>ddfdsf<Br>dfdsf<Br>dfdsf<Br>fdsf<Br>dfdsf<Br>dfdsf<Br>dfdsf<Br>dfdsf<Br>dfdsf<Br>dfdsf<Br>dfdsf<Br>dfdsf<Br></div>
    <div class="b">Foo<br>bar</div>
</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;
}

.wrapper {
/*  background-color: yellow; */
    overflow: auto;
}