PySide6 UI looks different depending on which macOS built Python

[axu2]

If I built an app using macOS 15 using Homebrew Python (the exact version doesn't seem to matter, I tried several), then the app looks the same on macOS 15/27.

However, if I built it using Homebrew Python on macOS 27, then the app looks different (and in my opinion, worse).

Is there any way to force the old look?

This is the old look:

I got user feedback that the new look looks bad, especially with the pure white background.

[miracletech322]

In my opinion, I suggest to use QStyleFactory class.
print(QStyleFactory.keys())
You can get available styles through call this function and, keep macos style.
Good luck to you.

[axu2]

calling setStyle('Windows') looks terrible on macOS, but that's expected.

calling setStyle('Fusion') looks OK but not ideal.

calling setStyle('macOS') doesn't change anything.

I think the problem is related to the python version, not Qt. since the red/yellow/green button in top left get liquid glassified.

[miracletech322]

Qt's macOS guidance describes adding this key to the app's Info.plist:

<key>UIDesignRequiresCompatibility</key>
<true/>
Please update Info.plist file and try again.

[axu2]

Yes, that worked, thank you!

where is the guide you mentioned?