The Box Model

Everything in CSS has a box around it, and understanding these boxes is key to being able to create layouts with CSS, or to align items with other items.

The full CSS box model applies to block boxes, inline boxes only use some of the behavior defined in the box model. The model defines how the different parts of a box — margin, border, padding, and content — work together to create a box that you can see on the page.

For a div element the default value for margin, border and padding is zero.