I got on the laptop this morning and the display, with the two CSS entries in place, is very good in Firefox, which was the worst of the three browsers. So this issue seems to be very much a function of whatever monitor the user has rather than the browsers themselves. So far, I’ve only seen the issue with the social icons. Everything else seems to display fine regardless of the monitor.
I’ll assume this is something to be address in your updates in general rather than a fix for a specific user, so I’ll consider this thread closed and look for it to be addressed in the future. BTW, I’m very happy with the Alora theme.