anchor.diff:  
       return DefaultFocusTraversal(
         policy: ReadingOrderTraversalPolicy(),
  -      child: PhysicalShape(
  -        elevation: 16,
  -        color: cranePrimaryWhite,
  -        clipper: ShapeBorderClipper(
  -          shape: RoundedRectangleBorder(
  -            borderRadius: BorderRadius.only(
  -              topLeft: Radius.circular(frontLayerBorderRadius),
  -              topRight: Radius.circular(frontLayerBorderRadius),
  +      child: Padding(
  +        padding:
  +            isDesktop ? EdgeInsets.zero : EdgeInsets.only(top: mobileTopOffset),
  +        child: PhysicalShape(
  +          elevation: 16,
  +          color: cranePrimaryWhite,
  +          clipper: ShapeBorderClipper(
  +            shape: RoundedRectangleBorder(
  +              borderRadius: BorderRadius.only(
  +                topLeft: Radius.circular(frontLayerBorderRadius),
  +                topRight: Radius.circular(frontLayerBorderRadius),
  +              ),
               ),
             ),
  -        ),
  -        child: ListView(
  -          padding: isDesktop
  -              ? EdgeInsets.symmetric(
  -                  horizontal:
  -                      isSmallDesktop ? appPaddingSmall : appPaddingLarge,
  -                  vertical: 22)
  -              : EdgeInsets.all(20),
  -          children: [
  -            Text(title, style: Theme.of(context).textTheme.subtitle),
  -            SizedBox(height: 20),
  -            ItemCards(index: index),
  -          ],
  +          child: ListView(
  +            padding: isDesktop
  +                ? EdgeInsets.symmetric(
  +                    horizontal:
  +                        isSmallDesktop ? appPaddingSmall : appPaddingLarge,
  +                    vertical: 22)
  +                : EdgeInsets.all(20),
  +            children: [
  +              Text(title, style: Theme.of(context).textTheme.subtitle),
  +              SizedBox(height: 20),
  +              ItemCards(index: index),
  +            ],
  +          ),
           ),
         ),
       );
  
positive.code:     Key key,
      this.title,
      this.index,
    }) : super(key: key);
  
    final String title;
    final int index;
  
    static const frontLayerBorderRadius = 16.0;
  
  
negative.code: 
  class _BackdropState extends State<Backdrop> with TickerProviderStateMixin {
    TabController _tabController;
    Animation<Offset> _flyLayerHorizontalOffset;
    Animation<Offset> _sleepLayerHorizontalOffset;
    Animation<Offset> _eatLayerHorizontalOffset;
  
    // How much the 'sleep' front layer is vertically offset relative to other
    // front layers, in pixels, with the mobile layout.
    static const _sleepLayerTopOffset = 60.0;
  
    @override
    void initState() {
      super.initState();
      _tabController = TabController(length: 3, vsync: this);
  
      // Offsets to create a horizontal gap between front layers.
      _flyLayerHorizontalOffset = _tabController.animation
          .drive(Tween<Offset>(begin: Offset(0, 0), end: Offset(-0.05, 0)));
  
      _sleepLayerHorizontalOffset = _tabController.animation
          .drive(Tween<Offset>(begin: Offset(0.05, 0), end: Offset(0, 0)));
  
      _eatLayerHorizontalOffset = _tabController.animation
          .drive(Tween<Offset>(begin: Offset(0.10, 0), end: Offset(0.05, 0)));
    }
  
  