Bordering on confusion

Hi folks — newb that I am, I somehow cleverly managed to make the gray borders around my widgets/sidebars vanish. (I have NO idea what I changed — just visited the site in progress on another machine.)

I guess I'm a bit confused about how to reinstate them. Would it be under ATA/Style Widgets? Sidebars? Layout? (Told you I was newb!) Which field? Basically, I'd like to recapture the rounded, #eeeeee-colored borders around both left and right sidebars, and above the center area between the header and the lower horizontal bar.

The site: http://test.clubbo.com/wp/

Thanks a zillion.