Opera Fonts

Suse 8.0 Opera has adopted a fairly small font when it displays its main window on my system. I just cannot see how to change it. The main menu - File, Edit, View, Navigation are all tiny fonts. I have had a look at the settings in contol centre >look and feel >fonts, but cannot see anything wrong. Fonts for displaying Web Pages can be changed and work ok -and my other applications display ok. Brian Marr