[Feature Request]: Follow Wallpaper Tinting and/or Blur on macOS

[CyanVoxel]

Checklist

• I am using an up-to-date version.
• I have read the documentation.
• I have searched existing issues.

Description

Currently TagStudio's windows do not follow macOS's "Allow wallpaper tinting in windows" option, which subtly tints application windows with a color from the users' desktop wallpaper. This seems to stem from Qt using a predefined opaque color as the default window background rather than using a transparent value.

When adding self.setStyleSheet("background-color: rgba(0, 0, 0, 0)") to setupUi() located inside main_window.py you can see it's possible to uncover this window tinting but with several issues that stem from the style sheets, well, cascading. Not shown are additional issues that arise when a library is open, such as scrollbars taking on a "Windows 9x" appearance.

What I would like to see is the application being able to fit in with other native macOS apps by using wallpaper tinting when applicable without causing unintended glitches with other widgets (i.e. black buttons, "Windows 9x" style scrollbars and combo boxes) and also not disrupting the UI on other platforms.

Solution

I believe that transparent backgrounds set via style sheets will get this most of the way there, especially by using selectors such as the following:
self.setStyleSheet("QMainWindow{background-color: rgba(0, 0, 0, 0)}")
Thumbnails/preview images will also need to be reworked a bit to allow for transparency. Finally I'm not sure about buttons, scrollbars, and combo boxes - the later two being difficult to apply custom themes to. If anything I feel the closer this can get to a native macOS look and feel while on the platform, such as adding native-looking scrollbars, would be in the spirit of this request.

Alternatives

1. There may be some third-party modules available to help with this, however I have not found any relevant to wallpaper tinting or any that are up to date with Qt 6.
2. Using the "Macintosh" theme while on Darwin (app.setStyle("macos")) may help, however I don't find most of that theme in line with modern macOS's appearance and seems to come with a host of other quirks.
3. Blurred windows backgrounds (aka acrylic on Windows) would be very cool but likely more difficult to get working, especially cross-platform.