I have the exact same version of Google Chrome (22.0.1229.94) on both my Mac (OSX 10.8.2) and my PC (Windows XP SP2) but my input buttons are being rendered slightly differently (the pc version is moved down slightly).
Here is shot of my devtools

Mac Version

PC Version

Obviously not a huge difference but enough to make it stand out. Any obvious flaws in my code?
I didn’t realize that my font sizes were different. That seems to be the issue.