When inspecting your template page, the CSS wikia returned is:
border-bottom: 1px none #ACB78D;
So there's the problem. You can fix this by using
border-bottom: 1px solid #ACB78D;
and you can get rid of the border-bottom-color property.

It looks like the borders are suppressed in other parts of the style sheet, and the black border you were looking at was actually the upper-border of the cell below.

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