boxsizing.html

<!DOCTYPE html>
<html lang="en">
<head>
<title>Box-sizing CSS Property</title>
<meta charset="utf-8">
<style>
* {
            box-sizing:border-box;
}
div {
            background:yellow;
            border:2px solid black;
            height:150px;
            padding:20px;
            margin:10px;
            width:30%;
            float:left;
}
</style>
</head>
<body>
<h1>box-sizing set to border-box</h1>
<div>
Element 1
</div>
<div>
Element 2
</div>
<div>
Element 3
</div>
<div>
Element 4
</div>
<div>
Element 5
</div>
<div>
Element 6
</div>
</body>
</html>