Hey everyone, don't forget about the
css calc ability 
.
Try changing the template code to this:
Code:
<ol id="forums" class="floatcontainer" style="max-width:calc(100% - 2px) !important;">
See if that does it. I hate using style= in any css call, I prefer to define any css changes in the actual definition but sometimes when you customize a style or theme from another software a direct inline edit is required else you'll pull your hair out trying to figure out where you went wrong along the way lol.
So by saying go 100% we will but then we tell it to remove the spare 2px we noticed it increased. By using max-width we told it not to be bigger than 100% but somewhere as you can all plainly see something else bumped it up, I'd imagine some additional padding added somewhere along the line while you were customizing your style.