the css constant 'safe-area-inset-top' appears to be correct in the iPhone X simulator.
On other devices running on iOS 11 however, it seems to be returning incorrect values.
I'm getting 20px when holding my iPhone 7 in landscape, and 0px when holding my phone in portrait.
This seems incorrect to me since the status bar is hidden in landscape, and visible in portrait. So I'd expect it to be the other way around, 20px in portrait and 0px in landscape.
In these screenshots I've created a square with css rule `top: constant(safe-area-inset-top);`