diff --git a/assets/markdown/strategy.md b/assets/markdown/strategy.md
index c0eccc0..4ba4b86 100644
--- a/assets/markdown/strategy.md
+++ b/assets/markdown/strategy.md
@@ -182,42 +182,25 @@ class _StrategyExampleState extends State<StrategyExample> {
               onClear: _clearOrder,
             ),
             const SizedBox(height: LayoutConstants.spaceM),
-            Stack(
+            Column(
               children: <Widget>[
-                AnimatedOpacity(
-                  duration: const Duration(milliseconds: 500),
-                  opacity: _order.items.isEmpty ? 1.0 : 0.0,
-                  child: Row(
-                    mainAxisAlignment: MainAxisAlignment.center,
-                    children: <Widget>[
-                      Text(
-                        'Your order is empty',
-                        style: Theme.of(context).textTheme.titleLarge,
-                      ),
-                    ],
-                  ),
+                if (_order.items.isEmpty)
+                  Text(
+                    'Your order is empty',
+                    style: Theme.of(context).textTheme.titleLarge,
+                  )
+                else
+                  OrderItemsTable(orderItems: _order.items),
+                const SizedBox(height: LayoutConstants.spaceM),
+                ShippingOptions(
+                  selectedIndex: _selectedStrategyIndex,
+                  shippingOptions: _shippingCostsStrategyList,
+                  onChanged: _setSelectedStrategyIndex,
                 ),
-                AnimatedOpacity(
-                  duration: const Duration(milliseconds: 500),
-                  opacity: _order.items.isEmpty ? 0.0 : 1.0,
-                  child: Column(
-                    children: <Widget>[
-                      OrderItemsTable(
-                        orderItems: _order.items,
-                      ),
-                      const SizedBox(height: LayoutConstants.spaceM),
-                      ShippingOptions(
-                        selectedIndex: _selectedStrategyIndex,
-                        shippingOptions: _shippingCostsStrategyList,
-                        onChanged: _setSelectedStrategyIndex,
-                      ),
-                      OrderSummary(
-                        shippingCostsStrategy:
-                            _shippingCostsStrategyList[_selectedStrategyIndex],
-                        order: _order,
-                      ),
-                    ],
-                  ),
+                OrderSummary(
+                  shippingCostsStrategy:
+                      _shippingCostsStrategyList[_selectedStrategyIndex],
+                  order: _order,
                 ),
               ],
             ),
diff --git a/lib/widgets/design_patterns/decorator/custom_pizza_selection.dart b/lib/widgets/design_patterns/decorator/custom_pizza_selection.dart
index 76d0c89..aa8429f 100644
--- a/lib/widgets/design_patterns/decorator/custom_pizza_selection.dart
+++ b/lib/widgets/design_patterns/decorator/custom_pizza_selection.dart
@@ -20,29 +20,49 @@ class CustomPizzaSelection extends StatelessWidget {
       children: <Widget>[
         for (var i = 0; i < pizzaToppingsDataMap.length; i++)
           i == 0
-              ? ChoiceChip(
-                  label: const Text(
-                    'Pizza Base',
-                    style: TextStyle(color: Colors.white),
-                  ),
+              ? _ChoiceChip(
+                  label: 'Pizza Base',
                   selected: true,
-                  selectedColor: Colors.black,
                   onSelected: (_) {},
                 )
-              : ChoiceChip(
-                  label: Text(
-                    pizzaToppingsDataMap[i]!.label,
-                    style: TextStyle(
-                      color: pizzaToppingsDataMap[i]!.selected
-                          ? Colors.white
-                          : Colors.black,
-                    ),
-                  ),
+              : _ChoiceChip(
+                  label: pizzaToppingsDataMap[i]!.label,
                   selected: pizzaToppingsDataMap[i]!.selected,
-                  selectedColor: Colors.black,
                   onSelected: (bool? selected) => onSelected(i, selected),
                 ),
       ],
     );
   }
 }
+
+class _ChoiceChip extends StatelessWidget {
+  const _ChoiceChip({
+    required this.label,
+    required this.selected,
+    required this.onSelected,
+  });
+
+  final String label;
+  final bool selected;
+  final ValueSetter<bool> onSelected;
+
+  @override
+  Widget build(BuildContext context) {
+    final color = selected ? Colors.white : Colors.black;
+
+    return ChoiceChip(
+      color: MaterialStateProperty.resolveWith((states) {
+        if (states.contains(MaterialState.selected)) {
+          return Colors.black;
+        }
+
+        return Colors.white;
+      }),
+      label: Text(label),
+      labelStyle: TextStyle(color: color),
+      checkmarkColor: color,
+      selected: selected,
+      onSelected: onSelected,
+    );
+  }
+}
diff --git a/lib/widgets/design_patterns/strategy/strategy_example.dart b/lib/widgets/design_patterns/strategy/strategy_example.dart
index b0b9a01..9d973ca 100644
--- a/lib/widgets/design_patterns/strategy/strategy_example.dart
+++ b/lib/widgets/design_patterns/strategy/strategy_example.dart
@@ -49,42 +49,25 @@ class _StrategyExampleState extends State<StrategyExample> {
               onClear: _clearOrder,
             ),
             const SizedBox(height: LayoutConstants.spaceM),
-            Stack(
+            Column(
               children: <Widget>[
-                AnimatedOpacity(
-                  duration: const Duration(milliseconds: 500),
-                  opacity: _order.items.isEmpty ? 1.0 : 0.0,
-                  child: Row(
-                    mainAxisAlignment: MainAxisAlignment.center,
-                    children: <Widget>[
-                      Text(
-                        'Your order is empty',
-                        style: Theme.of(context).textTheme.titleLarge,
-                      ),
-                    ],
-                  ),
+                if (_order.items.isEmpty)
+                  Text(
+                    'Your order is empty',
+                    style: Theme.of(context).textTheme.titleLarge,
+                  )
+                else
+                  OrderItemsTable(orderItems: _order.items),
+                const SizedBox(height: LayoutConstants.spaceM),
+                ShippingOptions(
+                  selectedIndex: _selectedStrategyIndex,
+                  shippingOptions: _shippingCostsStrategyList,
+                  onChanged: _setSelectedStrategyIndex,
                 ),
-                AnimatedOpacity(
-                  duration: const Duration(milliseconds: 500),
-                  opacity: _order.items.isEmpty ? 0.0 : 1.0,
-                  child: Column(
-                    children: <Widget>[
-                      OrderItemsTable(
-                        orderItems: _order.items,
-                      ),
-                      const SizedBox(height: LayoutConstants.spaceM),
-                      ShippingOptions(
-                        selectedIndex: _selectedStrategyIndex,
-                        shippingOptions: _shippingCostsStrategyList,
-                        onChanged: _setSelectedStrategyIndex,
-                      ),
-                      OrderSummary(
-                        shippingCostsStrategy:
-                            _shippingCostsStrategyList[_selectedStrategyIndex],
-                        order: _order,
-                      ),
-                    ],
-                  ),
+                OrderSummary(
+                  shippingCostsStrategy:
+                      _shippingCostsStrategyList[_selectedStrategyIndex],
+                  order: _order,
                 ),
               ],
             ),