How do I change fonts in the design/customize section now in v.9?

I just upgraded my site using Framework theme from ver. 8.5.1 to 9.2.1. I’m trying to use the Community Store and when I went to install the Payment Gateway, I discovered it required PHP v.8.1+. That PHP version crashed my site using the core version 8.5.1, so I upgraded. Now I have several new problems. Parallax no longer works and several, if not all, of my font sizes have changed - much smaller. When I go to Design/Customize/Page Customizations to try and adjust font sizes, I cannot find an option to do that. Has this been moved? If so, where? I’ve also looked for general documentation on using v.9 but not finding it. If someone could share a link, that would be great!