There is no appearance tab in my Safari preferences.
They killed off the appearance feature in Safari 2 or 3 years ago. Are you using Version 8.0.3 (10600.3.18)? Your post sent me scurrying and I remembered the old friend Tinkertool, sure enough it let me set the font which I did not know was possible. My freeper page is now happy. I am running the latest version of everything, always have.