Override styling in sidebar

The tables in the theme I’m using automatically put horizontal lines between each row, thanks to some handy css styling I’d assume. It’s fine in other areas of my site, but is there a way to override–or just hide, for that matter–the styling so that it ISN’T used in my sidebar?

Why: I’m using a table to overlay text on an image, and I don’t want the lines to show up at the top and bottom of my image. (I know there’s a way to overlay text with css, but I don’t want to go there for this project.)

Address: http://www.wedelcafe.com/menu-specials/

Thanks for any help!