margin color

[dotJoon]

border: 1px solid #BORDERCOLOR;

I can designate BORDER COLOR like the above.
How can I designate MARGIN COLOR?

[ralph.m]

Margins don't have a color. They just push elements apart. You could use a wide border instead, or you can have a background color showing in the padding area.

[felgall]

The margin colour will be whatever colour is assigned to the container that the elements are in. So simply set the required colour on the parent element.