f7723559_CSS_HTML_XHTML_Reference_Book__Description_and_notes
[Property/Values] border-top-color, border-right-color, border-bottom-color, border-left-color one color or inherit [Description and notes] 
for defining just the border's color on only one side of an element initial value: the value of the color property; not inherited
CSS HTML XHTML Reference Book
Description and notes