overlayStyleFor function

SystemUiOverlayStyle overlayStyleFor(
  1. WalletColors colors
)

System status-bar / nav-bar overlay style for a given scheme. Light theme → dark icons (visible on cream); dark theme → light icons. Applied via the AppBar theme AND globally in the MaterialApp builder (AppBar-less screens get no appBarTheme.systemOverlayStyle).

ICON BRIGHTNESS ONLY — statusBarColor/systemNavigationBarColor are deliberately NOT set: at targetSdk 36+ Flutter forces edge-to-edge and both fields are silent no-ops (mobile review fold); setting them would imply a contract the app cannot keep. On gesture-nav devices the nav brightness only affects the pill; 3-button nav gets full icon tinting.

Implementation

SystemUiOverlayStyle overlayStyleFor(WalletColors colors) {
  final isDark = colors.bg.computeLuminance() < 0.5;
  return SystemUiOverlayStyle(
    statusBarIconBrightness: isDark ? Brightness.light : Brightness.dark,
    statusBarBrightness: isDark ? Brightness.dark : Brightness.light, // iOS
    systemNavigationBarIconBrightness: isDark
        ? Brightness.light
        : Brightness.dark,
  );
}