Works quite well (on iOS), really good work! Here is a small issue I experience on a lot of mobile sites with embedded maps and also on yours:
If I zoom the page outside of the map and then scroll so that the map fills the full screen there is no way to zoom out/get away from the map again. You will just scroll and zoom the map and eventually will have to reload the page.
It also allows to scroll far out of bounds of the world which can be a bit confusing.
This happens with other UI elements as well like those instructive subscribe pop ups.
I'm not up to speed with the latest JS and browser features, but unless there is some sort of zoom reset from the browser itself I don't think there is an easy solution without making arbitrary decisions like "user has scrolled up 10 times, move entire page up"
For instance , if I shake my mobile (think google maps) or 3 finger Zoom out, then the browser resets the zoom level.
This is a problem I've noticed with a number of mobile-friendly sites that offer a full width map, regardless of how it is implemented.
However recently, there have been a number of occasions where embedded Google Maps instances have insisted (on iOS) the use of two fingers to scroll, helping solve the issues of being stranded within a map.
I believe this is a relatively recent problem caused by mobile safari removing the ability for sites to opt out of pinch zooming (because many sites were ignoring the accessibility importance of allowing users to zoom in).
If I zoom the page outside of the map and then scroll so that the map fills the full screen there is no way to zoom out/get away from the map again. You will just scroll and zoom the map and eventually will have to reload the page. It also allows to scroll far out of bounds of the world which can be a bit confusing.