HTML formatting being ignored in text widget

I am using Twenty Ten Theme (www.stephaniemojica.com) and am adding a newsletter signup box in the right sidebar. I figured out where to change the css to add spacing between my widgets at the right. However, when I place HTML in the text widget for the newsletter, the signup boxes and text (and the table itself) appears correctly, however I want the table background to be a color and the table border to be a color. Neither of these elements are showing up. I’ve looked for sidebar in the css. Basically not sure what I’m looking for – would have expected the text widget html to override.

Any help appreciated.