If you’ve learned CSS from the ground up, you should have a good understanding of the box model. But if you’re unfamiliar ...

In CSS, each of these rectangular boxes are described using the standard box model. This is a very important intersection between HTML and CSS that is essential to grasp as we learn HTML and CSS.

HTML and CSS use a box model, which means that page elements include margins, padding, background colors and, optionally, decorative borders. Open your HTML Web page in a text editor such as Notepad.