If you need to apply the .hint class to TDs, TRs, and the TABLE element itself, you need to slightly change your css declarations. Currently you "glue" those together, which is not correct for your scenario. Here is how you should change those instead:
//CSS goes here
In any case, our suggestion is, if you experience any problem, to first get your CSS style properly a test TABLE that is on the page and outside of the RadToolTip. Once you have it looking as expected, it should look good into the tooltip as well.
the Telerik team
Check out Telerik Trainer
, the state of the art learning tool for Telerik products.