anchor.diff:      Key key,
       this.title,
       this.index,
  +    this.mobileTopOffset,
     }) : super(key: key);
   
     final String title;
     final int index;
  +  final double mobileTopOffset;
   
     static const frontLayerBorderRadius = 16.0;
   
  
positive.code: 
  class _BackdropState extends State<Backdrop> with TickerProviderStateMixin {
    TabController _tabController;
    Animation<Offset> _flyLayerOffset;
    Animation<Offset> _sleepLayerOffset;
    Animation<Offset> _eatLayerOffset;
  
    @override
    void initState() {
      super.initState();
      _tabController = TabController(length: 3, vsync: this);
  
      // Offsets to create a gap between front layers.
      _flyLayerOffset = _tabController.animation
          .drive(Tween<Offset>(begin: Offset(0, 0), end: Offset(-0.05, 0)));
  
      _sleepLayerOffset = _tabController.animation
          .drive(Tween<Offset>(begin: Offset(0.05, 0), end: Offset(0, 0)));
  
      _eatLayerOffset = _tabController.animation
          .drive(Tween<Offset>(begin: Offset(0.10, 0), end: Offset(0.05, 0)));
    }
  
  
negative.code: 
      return DefaultFocusTraversal(
        policy: ReadingOrderTraversalPolicy(),
        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),
              ],
            ),
          ),
        ),
      );
  