That was the first thing I tried. When I installed Safari 10 and restarted the computer, all the print was tiny, so I immediately went to the "Advanced" settings, where the minimum font size used to live - but now, instead of a font size control, there was a zoom control. If I leave it at 100%, all the pages fit - at least all the ones I've tried so far - but the print is uncomfortably small. If I increase it to 150%, the print is better (though still smaller than I prefer), but now several pages - including this one, by the way - expand beyond the screen, and while I'm typing this reply, I have to keep sliding back and forth to see all my text.
But there's another problem: when you zoom, various things besides the text expand in random and unpredictable ways. Fields (for text or images) become much larger than they need to be, crowding out information I need to see - but the text inside those fields stays relatively small, so I have a big empty space with small print. This was easily solved in Safari 9 by expanding the font size, but I can't do that in Safari 10. Furthermore, in order to accommodate these expanded fields, Safari breaks the format of the page, moving everything around; so (for instance) instead of two things being visible side by side, they are now displayed above each other, and I now have to scroll vertically as well as horizontally, to see the content of that page.
