add gradient support to TooltipStyle and refactor unused params

README.md

@@ -221,9 +221,9 @@ SuperTooltip(
 )
 ```
 
-### AnimationConfiguration - Animation Timing
-
-Control animation behavior:
+### AnimationConfiguration - Animation Timing
+
+Control animation behavior:
 
 ```dart
 SuperTooltip(
@@ -235,10 +235,35 @@ SuperTooltip(
     exitDuration: Duration(milliseconds: 100),   // Hover exit delay
   ),
   // ...
-)
-```
-
-## 🎯 Common Use Cases
+)
+```
+
+### Overlay Selection
+
+Control which `Overlay` receives the tooltip entries:
+
+```dart
+SuperTooltip(
+  useRootOverlay: true, // default: insert into the app's root Overlay
+  content: const Text(
+    'I use the global overlay by default.',
+    style: TextStyle(color: Colors.white),
+  ),
+  child: const Icon(Icons.layers),
+)
+```
+
+- `useRootOverlay: true` - Insert into the root/global `Overlay` and keep the tooltip above subsequently presented routes
+- `useRootOverlay: false` - Insert into the nearest local `Overlay` and follow the local route layering
+- Default is `true`, so existing usages may change layering behavior after upgrading
+
+Use `false` when the tooltip must stay scoped to a nested `Overlay`, such as a
+custom overlay region, embedded navigator, or other locally managed floating
+content. In route-based surfaces like dialogs or bottom sheets, `false` allows
+newly presented routes to naturally cover the tooltip instead of forcing the
+tooltip to the global top layer.
+
+## 🎯 Common Use Cases
 
 ### Auto-Positioning Tooltip
 
@@ -455,17 +480,18 @@ SuperTooltip(
 )
 ```
 
-### Touch-Through Areas
-
-Allow touches to pass through specific areas:
-
-```dart
-SuperTooltip(
-  controller: _controller,
-  touchThroughArea: Rect.fromLTWH(100, 100, 200, 100),
-  touchThroughAreaShape: ClipAreaShape.rectangle,
-  touchThroughAreaCornerRadius: 10.0,
-  barrierConfig: const BarrierConfiguration(show: true),
+### Touch-Through Areas
+
+Allow touches to pass through specific areas. The builder receives the target
+child's global rect and returns the final pass-through rect:
+
+```dart
+SuperTooltip(
+  controller: _controller,
+  touchThroughAreaBuilder: (area) => area.inflate(12),
+  touchThroughAreaShape: ClipAreaShape.rectangle,
+  touchThroughAreaCornerRadius: 10.0,
+  barrierConfig: const BarrierConfiguration(show: true),
   content: const Text("Tutorial step 1"),
   child: const Icon(Icons.lightbulb),
 )