Just as for the border-width, the border-color will NOT work unless you also include the border-style FIRST.
A dotted red border
A double green border
The div in the head tag produces what looks like a table with rounded corners and a double border. But I had to use a table tag (with border="0") to get this centered on the screen. Please see the Border Radius tutorial link (below) for more info about this effect.
Remember to include a DOCTYPE tag, such as <!DOCTYPE html>
Border Styles Introduction ~ 2 ~ 3