apancik/iphone-as-a-webcam ? reverse-engineered prompt

Build me a simple webpage that turns an iPhone into a webcam feed.

I want to open it on my phone, tap a button to use the back camera, and then hide all the extra controls so the camera preview can go full screen and look clean. It should be easy to use on an iPhone, with a big button for starting the camera, a button for full screen, and a way to make the video fill the whole display as much as possible. If there are any small tips or on screen instructions, keep them minimal and helpful.

Make it work well for plugging the phone into a Mac and using it as a camera source in other apps. Please keep the page lightweight and focused on just this one job, and look up current browser behavior online if you need to.