Howdy, @isa1978! Thanks for writing in…the typography options for the theme have not changed since our latest major update. We are in the process of updating some screenshots in our documentation, but everything mentioned here still stands:
The Content Font size there is a micro-adjustment for fonts only within the main content of a traditional page / post template, but if you want to adjust the global font-size, you will want to find the Root Font Size settings section, as that will set the very base options for your sizing. If you are unsure of what rems are, I would recommend reading up on some various CSS units as they all serve a different purpose based on how you want to approach things:
https://developer.mozilla.org/en-US/docs/Learn/CSS/Building_blocks/Values_and_units
The Root Font Size settings will allow you to set how the base sizing of fonts changes across viewports. Definitely make sure to check out that documentation article mentioned above as it will help a lot.
Cheers!