Type That Grows

Ask a room of designers which accessibility feature has the most users and you'll hear guesses about VoiceOver. It isn't close: it's text size. Surveys of iPhone users put larger-than-default text among the most enabled settings on the platform — a population that includes low-vision users, everyone over forty-five, and anyone who's ever read a recipe from across the kitchen.

Yet the canonical mobile screen is still designed once, at default size, on a designer's phone, at arm's length, by someone under forty with corrected vision. Then it meets the real world at 135%, and the truncation begins.

The failure modes are predictable: fixed-height rows that clip ascenders, labels that truncate into 'Confirm pa…', side-by-side pairs that collide, text baked into images that never scales at all. The fixes are equally predictable, which is the good news. Let containers grow with their content. Let horizontal pairs stack when type gets large — the platforms provide exactly this. Never fix a height on anything that holds text. And test at the accessibility sizes, where body text roughly triples, not just the first notch of the slider.

One discipline covers most of it: design the 100% version and the 235% version of every key screen. If the layout survives both, the sizes in between take care of themselves.