The margin property sets the margins of an element. If four values are given, they apply to top, right, bottom, and left margin, respectively.

If one value is given, it applies to all sides. If two or three values are given, the missing values are taken from the opposite side.

[ <length> | <percentage> | auto | inherit ]{1,4}

body { margin: 1em 2em 3em } /* top=1em, right=2em, bottom=3em, left=2em */

body { margin: 2em }         /* all margins set to 2em */