JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE>
<div class="red">
</div>
<div class="yellow">
</div>

CSS

.yellow {
	background: yellow;
	height: 300px;
}

.red {
	background: red;
	height: 300px;
}

@media screen and (min-width:600px) {
	.yellow, .red {
		float:left;
        width:50%;
	}
}