Ionic 4 tabbar on ios pwa

Hello Guys,

I am building a PWA with ionic 4, it works perfectly in the browser but when added it to the home screen to be standalone PWA, I faced this problem

there is a space bellow the tabbar,

and when i added this line to variables.scss:

ion-app {

another problem appeared:

There is a part of the body is covering the tabbar,

on android it works nicely without any problems, the problem is on iOS (ipad and iphone 7 plus)

What is the problem here?
Did anyone faced this before?
How to solve it?