<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>박스 모델 3</title>
<style>
div{
box-sizing: content-box;
width: 100px; height: 100px;
border: 5px solid darkgreen;
padding: 30px;
}
</style>
</head>
<body>
<div></div>
</body>
</html>