I seem to remember this conversation coming up at the FleetWorkshop before. I think ultimately what we discovered was that people were able to change their global phone accessibility settings to get this to work, which seems like the correct way to handle it (those who need it probably need it across their phone’s UI), since changing it at the CSS level would mean imposing the large font on those who don’t want or need it. Only ugly hack, of course, is just to pinch-zoom on iOS, but of course that means you lose text wrapping to the viewport size.