In mobile popup windows are extremely zoomed

Popup windows look strange: at first opening they are zoomed at max, so you need to close keyboard firstly and then make zoom as you need and then fill the form (login form, registration form, administration form)

Test scenario
Steps:
1. Press login button (or registration, or administration)

Actual result
Window is zoomed at max and user needs to make window smaller.

Expected result
Window is zoomed at normally size.