The following table show how nested tables inherit colors from the wikitable class (here it was renamed "global").

Global table
TH: should have pink bg
TD: white bg
Nested table
Nested TH: transparent | Nested TD: transparent

With child selector we could limit the wikitable styling to the direct childs of the table. Unfortunately, Internet Explorer 6.0 does not support child selector. See our bug #33752.

Global table
TH: should have pink bg
TD: white bg
Nested table
Nested TH: transparent | Nested TD: transparent

NOTE:The nested caption keep the green background. The nested table keep the black border. This is because those declarations are global so we did not reset them.