Might be good to know: I'm using the Safari browser on an iPhone.
Probably page is even more useable on a chrome or firefox browser.
Sorry, haven't tested that yet.
Here are some shoots and examples
I have no scrolling possibilities (inside the message box - I can only scroll outside of the box, the background)
like I have on the webpage. In this case I received 5 new messages but have only access to the visible ones -
in this case 2 since I cannot scroll down or even scale them down.
I have no scaling of the box.
Scaling is only for the whole screen but not the content of the box (but this is the dominant part where the relevant info is in)
and btw. If phone is used upright, text remained unscaled and overwrites other elements. See user picture and text.
Screenshot from the message area and one corrrespondence.
This one blue box in the foreground is very dominant and
partially covers the text in the background
However, you are right when you say it is usable.
Maybe I've exaggerated a bit here.
The main problem are probably the boxes, which are unfortunately not
scalable in themselves, but only the entire picture. Unfortunately, this
does not make the content any clearer.