The CSS box model is essentially a box that wraps around HTML elements, and it consists of: margins, borders, padding, and the actual content.

The box model allows us to place a border around elements and space elements in relation to other elements.

The image below illustrates the box model:

Explanation of the different parts:

• Margin – Clears an area around the border. The margin does not have a background color, and it is completely transparent
• Border – A border that lies around the padding and content. The border is affected by the background color of the box
• Padding – Clears an area around the content. The padding is affected by the background color of the box
• Content – The content of the box, where text and images appear

In order to set the width and height of an element correctly in all browsers, you need to know how the box model works.