JSFiddle - React, Tailwind, and code Playground

HTML

<html>
<body>

<div class="d1">
1<br/>
1<br/>
1<br/>
</div>

<div class="d2">
2<br/>
2
</div>

<div class="d3">
3
</div>

</body>
</html>

CSS

*{
  margin: 0;
  padding: 0;
}

.d1, .d2{
  width:50vw;
}

.d1{
  background-color:#f00;
  float: left;
}

.d2{
  background-color:#0f0;
  float: right;
}

.d3{
  background-color:#00f;
  clear: both;
}