JSFiddle - React, Tailwind, and code Playground

HTML

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>float height:100% error</title>
<style type="text/css">
html, body{
		height:100%;
}
body{
	margin:auto;
}
#main{
	overflow:hidden;
	width:50%;
	min-height:70%;
	margin:auto;
	background:#ccf;
}
#left{
	float:left;
	width:50%;
	min-height:100%;
	background:#ffc;
}
</style>
</head>
<body>
<div id="main">
	<div id="left">Плавающий блок</div>
</div>
</body>
</html>