Fun thing about Apple Safari on iOS the bars that are not removable takes like 100px of the total height resulting in a 400px height canvas for your website and add the keyboard over this to have some fun.
Composer design ideas
enhancement for mobile layout so this kind of stuff doesnt happen
what do you think?
Looks good, another improvement would be to make the composer a regular element in the body instead of static positioned div overlayed on top of everything else on mobile.