macOS support

Main.py

@@ -19,8 +19,8 @@ def _SetCursorThemeFallback() -> None:
     """GTK's cursor lookup reads XCURSOR_THEME directly; it isn't always inherited
     from the desktop session (shows as 'Unable to load ... from the cursor theme').
     Fill it in from gsettings if missing, so the warning has nowhere to come from.
-    GTK/GNOME only: nothing to do on Windows."""
-    if os.environ.get("XCURSOR_THEME") or sys.platform == "win32":
+    GTK/GNOME only: nothing to do on Windows or macOS."""
+    if os.environ.get("XCURSOR_THEME") or not sys.platform.startswith("linux"):
         return
     try:
         Result = subprocess.run(
@@ -250,7 +250,7 @@ def Main(Page: ft.Page) -> None:
 
 
 if __name__ == "__main__":
-    if "--portal-service" in sys.argv and sys.platform != "win32":  # Linux's file-picker portal only
+    if "--portal-service" in sys.argv and sys.platform.startswith("linux"):  # Linux's file-picker portal only
         # No Flet page at all here — the D-Bus FileChooser backend is a
         # plain asyncio service (see PortalService.py) that
         # spawns *this same executable* again with --pick-* flags for the