CSS: Margin vs Padding

What's the difference between CSS's margin and padding?

padding is the area inside the border.

margin is the area outside the border.

border is between margin and padding. [see CSS: Border]

Padding

The code:

div {padding: 1rem 2rem 3rem 4rem}

is a shorthand to the following:

div
{
padding-top: 1rem;
padding-right: 2rem;
padding-bottom: 3rem;
padding-left: 4rem;
}

Padding cannot be negative.

“padding” can have 1 to 4 values, separated by space:

1. padding: all_sides
2. padding: top_bottom left_right
3. padding: top left_right bottom
4. padding: top right bottom left

Margin

this code:

div {margin: 1rem 2rem 3rem 4rem}

is equivalent to the following:

div
{
margin-top: 1rem;
margin-right: 2rem;
margin-bottom: 3rem;
margin-left: 4rem;
}

Margin can be negative.

“margin” can have 1 to 4 values, same as padding.

Reference

Box model#propdef-padding

Box model#propdef-border

Box model