Remember the two new CSS properties, padding and margin, from the previous lesson? They are part of a concept called the "Box Model".

The browser sees every element as a box of content. Boxes have a width and height and an aspect ratio. They can also have a border. Within the box (between the border and the content) we can have some space, and this is called padding. Outside the box we can use margins to push the box away from other elements and position it on the page.

Imagine a framed picture. The space around the frame is the margin. The frame itself is the border. The mount inside the frame is the padding. And the picture itself is the content.