EXAMPLE
Run 
<!doctype html>
	<html>

<head>
	<title>Border-top-width property in CSS</title>
	<style type="text/css">
		div {
		  border: 1px solid purple;
		  margin: 1em 0;
		}
		
		div:nth-child(1) {
		  border-top-width: thick;
		}
		div:nth-child(2) {
		  border-top-width: 2em;
		}
	</style>
</head>

<body>
	<div>Element 1</div>
	<div>Element 2</div>
</body>
</html>