Increasing the width of Appointments days in calendar with sidebars

I cannot seem to find a way to increase the size of the calendar for appointments if I have a sidebar in play. Is there somewhere in the css file where I could try to tweak this a bit? I'll leave the sidebar on here so you can see what I mean - without the sidebar, the calendar is fine. With the sidebar, two digit dates will stack!

http://concierge.hellmund.net/pet-sitting/

Thanks

Danita