Hi Elisa… strange because it shouldn’t be different, or at least very minimal. I just looked at the live demo site for Preference in Chrome (which I use), Firefox, IE, Opera, and Safari, but the text sizes are basically matching each other. Usually if a font is different in size that is very noticeable, it could be a couple things…
1. the browsers have the text size settings to be smaller
2. content that was added to the site was copy and pasted with inline styling that could change their sizes
Do you have a link to your site and I can take a look and see if there is something causing the different sizes?