Menu bar off-center (Ruby Theme)?

So, last week, I noticed that the primary menu bar on my site was off-center (I also believe the color and type of font used in the menu may have changed but I’m not definite on both of those; I’m pretty certain I originally had the font set to be white rather than gray but I remember it being in some sort of sans serif/arial style font). I at first thought maybe it was just like this on my computer, so I had someone pull up my site on their computer and it looked the same on theirs. I left it for a day or two, thinking maybe the site had just done some update that temporarily altered the appearance of the primary menu bar, however, it still looks the same. This isn’t a major issue, but I’d like to fix it as it does look a bit sloppy and/or unprofessional.

My WordPress site is hosted through Bluehost, and I’m currently using the Ruby Theme which is perfect for what I want with my site (it’s a blog of sorts). I like the primary menu as-is, other than the fact that it’s now off-center and the font seems to have changed; other than that, it still functions as it should – really this is something of a cosmetic issue. Can anyone tell me how to fix this and what causes it so I can hopefully ensure the menu stays the way I want it in the future? Thank you!

Note: If this isn’t the correct forum for this question, I apologize; I’m new to the WordPress forums, please let me know which forum is the correct one and I can move this question over there.

The page I need help with: [log in to see the link]