fix: react to ConfettiWidget colors updates

lib/src/confetti.dart

@@ -343,6 +343,14 @@ class _ConfettiWidgetState extends State<ConfettiWidget>
     }
   }
 
+  @override
+  void didUpdateWidget(ConfettiWidget oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (widget.colors != oldWidget.colors) {
+      _particleSystem.colors = widget.colors;
+    }
+  }
+
   @override
   Widget build(BuildContext context) {
     return LayoutBuilder(

lib/src/particle.dart

@@ -80,7 +80,7 @@ class ParticleSystem extends ChangeNotifier {
   final double _blastDirection;
   final BlastDirectionality _blastDirectionality;
   final double _gravity;
-  final List<Color>? _colors;
+  List<Color>? _colors;
   final Size _minimumSize;
   final Size _maximumSize;
   final double _particleDrag;
@@ -105,6 +105,8 @@ class ParticleSystem extends ChangeNotifier {
     _setScreenBorderPositions();
   }
 
+  set colors(List<Color>? colors) => _colors = colors;
+
   void stopParticleEmission({bool clearAllParticles = false}) {
     _particleSystemStatus = ParticleSystemStatus.stopped;
     if (clearAllParticles) {

test/confetti_test.dart

@@ -1,6 +1,9 @@
-import 'package:flutter_test/flutter_test.dart';
+import 'dart:math';
 
 import 'package:confetti/confetti.dart';
+import 'package:confetti/src/particle.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
 
 void main() {
   group('ConfettiController', () {
@@ -20,4 +23,105 @@ void main() {
           throwsAssertionError);
     });
   });
+
+  group('ParticleSystem', () {
+    test('updates colors via setter', () {
+      final system = ParticleSystem(
+        emissionFrequency: 0.02,
+        numberOfParticles: 10,
+        maxBlastForce: 20,
+        minBlastForce: 5,
+        gravity: 0.2,
+        blastDirection: pi,
+        blastDirectionality: BlastDirectionality.directional,
+        colors: const [Colors.blue],
+        minimumSize: const Size(20, 10),
+        maximumSize: const Size(30, 15),
+        particleDrag: 0.05,
+      );
+
+      system.colors = const [Colors.red];
+
+      // Start emission to generate particles
+      system.startParticleEmission();
+      system.screenSize = const Size(400, 800);
+      system.update(0.016);
+
+      final particles = system.particles;
+      expect(particles.isNotEmpty, isTrue);
+      // All generated particles should use the updated color (red, not blue)
+      for (final particle in particles) {
+        expect(particle.color, equals(Colors.red));
+      }
+    });
+
+    test('colors setter affects newly generated particles', () {
+      final system = ParticleSystem(
+        emissionFrequency: 0.02,
+        numberOfParticles: 10,
+        maxBlastForce: 20,
+        minBlastForce: 5,
+        gravity: 0.2,
+        blastDirection: pi,
+        blastDirectionality: BlastDirectionality.directional,
+        colors: const [Colors.blue],
+        minimumSize: const Size(20, 10),
+        maximumSize: const Size(30, 15),
+        particleDrag: 0.05,
+      );
+
+      system.startParticleEmission();
+      system.screenSize = const Size(400, 800);
+      system.update(0.016);
+
+      // First batch should be blue
+      for (final particle in system.particles) {
+        expect(particle.color, equals(Colors.blue));
+      }
+
+      // Update colors and generate new particles
+      system.colors = const [Colors.green];
+      system.stopParticleEmission(clearAllParticles: true);
+      system.update(0.016); // finish
+
+      system.startParticleEmission();
+      system.update(0.016);
+
+      // New batch should be green
+      for (final particle in system.particles) {
+        expect(particle.color, equals(Colors.green));
+      }
+    });
+  });
+
+  testWidgets('ConfettiWidget rebuilds with updated colors', (tester) async {
+    final controller = ConfettiController();
+
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Scaffold(
+          body: ConfettiWidget(
+            confettiController: controller,
+            colors: const [Colors.blue],
+          ),
+        ),
+      ),
+    );
+
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Scaffold(
+          body: ConfettiWidget(
+            confettiController: controller,
+            colors: const [Colors.red],
+          ),
+        ),
+      ),
+    );
+
+    // Widget should not throw when rebuilt with new colors
+    expect(tester.takeException(), isNull);
+
+    controller.dispose();
+  });
 }