BUG:window controls overlap the navbar when app is maximized.

### Is there an existing issue for this?

- [x] I have searched the existing issues

### What happened?

On macOS when i tried using PictoPy app in a maximized window(full screen), the system window controls (red/yellow/green buttons) overlap with the application's top navigation panel.
This makes the navbar partially hidden, affecting usability.

Expected Behaviour
The navbar should have enough top padding/safe-area spacing so it does not get covered by macOS window controls.

Actual Behaviour
The macOS window controls overlap the navbar area in full screen mode.

### Record

- [x] I agree to follow this project's Code of Conduct