Font size change in admin area & website

I’m looking for some help on resolving a font size issue. This is no theme css problem, because the font size has changed my admin section in all 4 wordpress installs. I would say it’s a plugin, but that doesn’t make sense considering the other wordpress installs don’t have the same plugins. Does anyone know of a css file that controls everything on the server or is this a virus?

Here are my sites:
https://www.boisestatepublicradio.org/
https://www.boisestatepublicradio.org/podcasts
https://www.boisestatepublicardio.org/programming

Thanks in advance