The app looks different at real device

Have you included XWalk on your build set-up? It could be due to the native browser on the android device being outdated...
Chances are you have a custom/outdated version of the Android stock-browser or Chrome. It's a good practice to also setup Xwalk for your project to ensure that a consistent webview is used for all systems.

http://ionicframework.com/docs/cli/browsers.html