Comment numbers out of whack

My comment numbers for each thread are somewhat screwed up and I haven’t any idea why. I’ve messed around with the CSS for what should fix the problem, but nothing does and as you can tell by visiting my site, the comments start out with a margin that is acceptable, but as you scroll down the comments move a bit, ever so slightly to the left until you can no longer see the entire comment numbers.

Any help would be greatly appreciated.