How to make ionic responsive to all devices screen sizes

Hi guys, recently I have created an app and been working on different screen sizes via CSS. I tried to adjust to expected. However, when exported to real devices and not in google developer menu. I realise that sizes are different. Subsequently, I found out of viewport. Any advice to adjust my app suitable for all devices.

The only solution out there now is using media queries.
Check CSS3 media queries. It will do the job.