Struggling to get any browser on iOS devices (iPhone + iPad) to render input date and time fields properly? I managed to fix it with the following CSS:
input[type="date"], input[type="time"] { min-height: 2.5rem; min-width: 95%; }
Without this you get a tiny box on iOS which is too hard to click. With it you get a reasonable size, at the cost of it being a bit larger than normal on devices not locked within the Apple walled garden. You can see it in action on Pick a Date.