anchor.diff:  import 'scaffold.dart';
   import 'theme_data.dart';
   import 'theme.dart';
  -import 'typography.dart';
   
   // https://material.google.com/components/snackbars-toasts.html#snackbars-toasts-specs
   const double _kSnackBarPadding = 24.0;
  
positive.code:     }
      CurvedAnimation heightAnimation = new CurvedAnimation(parent: animation, curve: _snackBarHeightCurve);
      CurvedAnimation fadeAnimation = new CurvedAnimation(parent: animation, curve: _snackBarFadeCurve, reverseCurve: const Threshold(0.0));
      ThemeData theme = Theme.of(context);
      return new ClipRect(
        child: new AnimatedBuilder(
          animation: heightAnimation,
  
negative.code:               elevation: 6,
                color: _kSnackBackground,
                child: new Theme(
                  data: darkTheme,
                  child: new FadeTransition(
                    opacity: fadeAnimation,
                    child: new Row(
  