Problems with adaptive on Samsung GALAXY and iPhone. How to decide?

Question

css

The form on the mobile version has slid down and to the right (I can't show the code...). It uses flexbox and nothing else.
All other androids are fine. Who faced this (what would something move somewhere, although on other devices the norms)? And how can I check the performance on a device that is not on hand? How can you find out what's the matter in such cases, test the layout not on device resolutions, but how it will work on this particular device?

Answer 1

It’s hard to navigate without code, but there are such services for testing on different devices: https://www.browserstack.com/ shareware, 30 minutes, but if I’m not mistaken, you can re-register when the time ends up on another box, here’s a free www. responder.com

Answer 2

The eternal question of a mobile developer. My answer, you need the device itself. Because its different updates also behave differently. Emulators on xamarin are also of limited use. For example https://forums.xamarin.com/discussion/56298/diff...