The CSS Box Model

All HTML elements are considered as boxes. In CSS, the term "box model" is used when talking about design and layout.

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 add a border around elements, and to define space between elements.

The image below illustrates the box model:

Explanation of the different parts:

• Content - The content of the box, where text, images and nested html elements appear
• Padding - Clears an area around the content. The padding is transparent
• Border - A border that goes around the padding and content
• Margin - Clears an area outside the border. The margin is transparent

consider this example

div {
    width: 100px;

    padding: 10px;
    border: 15px solid gray;
    margin: 0; 
}

total width of div = 100px + (10px left padding + 10px right padding) + (15px left border + 15px right border) = 150px