Changing the default text size

Idk how to link the setting (which is possible), but back on sync for reddit I got annoyed with this too.

After changing the font sizes for posts and comments like you did, I realized there is a setting under "General" that allows you to change the base font size. Doing so affects all of the font sizes without having to configure each individual section.

That said, it is very easy to scroll past or overlook that setting.