Demo

style.css
index.html

body {
	font-family: sans-serif;
	padding: 20px;
}

div {
	background-color: deepskyblue;
	border-top: solid black 4px;
	padding: 10px;
}

div {
	border-top-color: black; /* Non-shorthand. */
	border-top-style: solid;
	border-top-width: 4px;
}

<!DOCTYPE html>
<html>
	<head>
		<title>Border</title>
		<link href="/assets/styles/reset.css" rel="stylesheet">
		<link href="style.css" rel="stylesheet">
	</head>
	<body>
		<section>
			<div>
				<p>This is some text in the first element.</p>
			</div>
			<div>
				<p>And some more in the second element.</p>
			</div>
			<div>
				<p>Then a third one, too.</p>
			</div>
		</section>
	</body>
</html>