CSS Box Model
The CSS box model describes how elements are structured in terms of content, padding, border, and margin.
<!DOCTYPE html>
<html>
<head>
<style>
.box {
width: 200px;
padding: 10px;
border: 5px solid black;
margin: 20px;
}
</style>
</head>
<body>
<div class="box">This is a box!</div>
</body>
</html>