I have been using my iMac for only a couple of weeks now, but during that time I have searched high and low for a setting to adjust the size of the font on the Safari browser - NOT the text on the web pages it displays (I figured that bit out!), the text on the actual browser frame itself e.g. the bookmark title, the titles displayed on the tabs etc
I also have not figured out how to increase the size of the text on the navigation bar at the top of my iMac where all of the available options for the program in use are displayed (file, edit, view and so forth)...
I am very pleased with the Mac overall, but the issue of these tiny weeny text sizes on the Mac navigation systems is a problem - anyone with real eyesight troubles would certainly be in a pickle!
Hopefully someone here will know what to do - I guess I just haven't found the secret yet!
Sorry, but you can't change the size of the fonts or the menus in application windows. They aren't that small, so if you have trouble seeing them, you can use the Zoom feature of Universal Access to enlarge everything you move your mouse over. It's in System Preferences.
paradox -- The other thing you can do is go to Safari Preferences, then click on "Advanced." Where is says "Never show fonts smaller than . . ." try different sizes. The default I believe is 9. Up it to where you like it better.
You can either change your screen resolution (system presences/ DISPLAYS) to make the menus bigger or use the screen zoom, described above. You'll find this too in the system preferences under Universal Access.