The model cannot see your device, so ask it to reason about the difference between the two environments instead of about your code. I get a check I can run on the phone rather than a speculative patch.
This works in the desktop browser and fails on my phone. Do not change code yet.
Device and OS:
Browser:
What I see:
List what differs between those two environments for this feature, ranked by likelihood: viewport size, touch versus mouse events, iOS Safari behaviour (100vh, position: fixed, date inputs), slower network, storage blocked in private mode, camera or clipboard permissions.
For the top one, tell me the single thing I can check on the phone to confirm it.
AskVibe