I love seeing open feedback loops like this. Thanks for being open to feedback and willing to include it.
So is that demo page a default from Bootstrap or some such?
If I'm not mistaken Bootstrap recommend against using "user-scalable=no", so it's probably not a default page.
It is not, we often use own little helper https://github.com/720kb/csshelper plus custom classes, but the zoom must be my mess, when you are 24h on a desktop you forgot 99% population is on a phone :)