Property Reference - CSS Reference - page 218

Name
margin-top
Values:
<length> | <percentage> | auto
Initial value:
0
Applies to:
All elements
Inherited:
No
Percentages:
Refer to the width of the containing block
Computed value:
For percentages, as declared; for length values, the absolute length
Description:
Defines the width of the top margin for an element. Negative values are permitted, but caution
is warranted (see margin ).
Examples:
ul {margin-top: 0.5in;}
h3 {margin-top: 1.5em;}