For Cupertino widgets, we need to figure out how to scale our text sizes so that when someone asks for a "headline" or other named sizes on iOS, they get the size that they expect.

On Android, there is a single FONT_SCALE (a double) that scales the font based on a system preference, but on iOS, the font size preference doesn't scale linearly with the different font usages. For instance, an Extra Extra Extra Large headline on iOS is 18% larger, whereas a footnote is only 15% larger, and an "Extra Large" headline is 5% larger, while an "Extra Large" caption3 doesn't change size at all.

(table from this stackoverflow post)

In order to make sure that Cupertino assets get the sizes that match what iOS does, we'll probably need to change the tables in typography.dart so that instead of fixed values for the font sizes, we do something more clever on each platform based on the preferred type size and the usage for the font.