variantFor method
Retrieves the appropriate theme variant based on the resolved brightness.
Uses the four-level cascade: brightness override → Cupertino pin → Material ThemeMode → system/device. This ensures the correct variant is selected even when the device OS and app theme differ.
Implementation
GlassThemeVariant variantFor(BuildContext context) {
// Level 1: own brightness override takes absolute priority.
// Levels 2-4: delegated to the package-private utility.
final b = brightness ?? resolveGlassBrightness(context);
return b == Brightness.dark ? dark : light;
}