Making app responsive for varying screen sizes

[jai-k-gohil]

No consistent app look and feel across various screens!

To reproduce issue

• Try testing app on varying devices in simulator.

This is how it looks on Iphone 11 Pro Max.

[afgprogrammer]

This should not happen, because we set a default height value for SliverAppBar and for another part like the main category you have to apply some styles.