A stretched website in an app shell is instantly recognisable, and it is the AI default: desktop spacing, ignored platform conventions, motion that fights the OS. This skill designs mobile screens from platform rules first: iOS Human Interface Guidelines or Material 3, never one skin shipped to both.
The foundations it locks: respect the platform body face where it helps but choose a deliberate display face for brand moments, define touch targets at 44pt or 48dp, and decide safe areas and gesture zones before a single screen is drawn. References are gathered by role, onboarding, home, detail, empty state, paywall, from apps that match the register of the thing being built.
Road to Selah, VitalDial, and Ìmọ̀ were all designed under this skill. The App Store screenshots on this site are its output.