14. Margin and Padding Properties

margin: length | percentage | auto

Set margin width.
Percentage is relative to the width of the containing block.

padding: length | percentage

Set padding width.

margin and padding actually take up to 4 values: top right bottom left.

Right defaults to the same as top.
Bottom defaults to the same as top.
Left defaults to the same as right.

margin-{top,right,bottom,left}

Sets the size of a margin on one side.

padding-{top,right,bottom,left}

Sets the size of the padding between the content and border, on one side.