By setting the width and height of an element, we're actually setting the size of its content.

The total dimensions include its padding, borders and margins.

<html>
 <head>
  <style>p {background-color: #44b3c2;width: 150px;height:100px;padding: 25px;border: 25px solid #f1a94e;margin: 25px 0px;}</style>
 </head>
 <body><p>I'm the actual content.</p></body>
</html>
]]>

Sweet! Including the paragraph's padding, borders and margins on every side, its total width is 300px; its total height is 200px.

Don't these values call for a shorthand property?