Theme format problems with Firefox & 2.5

I am trying the 2.5 wp up from 2.3. The formating for my theme Cutline 1.3 column right worked fine on 2.3 but now when I go to an archive to read the whole post the text becomes small and italic and the right hand divs go to the bottom of the post. Every thing else including the front page works fine and the issue is just with Firefox on Mac and PC. Safari and IE7 don’t have this issue. Is anyone else experiencing this problem and if so is it a wordpress or theme designer issue?