update

lib/core/services/card_color_service.dart

@@ -0,0 +1,27 @@
+import 'package:flutter/material.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+class CardColorService {
+  static const _key1 = 'card_color_primary';
+  static const _key2 = 'card_color_secondary';
+
+  // defaults match existing gradient: Color(0xFF6B5DD3) and Color(0xFF2A2040)
+  static const defaultPrimary = Color(0xFF6B5DD3);
+  static const defaultSecondary = Color(0xFF2A2040);
+
+  static Future<(Color, Color)> load() async {
+    final prefs = await SharedPreferences.getInstance();
+    final c1 = prefs.getInt(_key1);
+    final c2 = prefs.getInt(_key2);
+    return (
+      c1 != null ? Color(c1) : defaultPrimary,
+      c2 != null ? Color(c2) : defaultSecondary,
+    );
+  }
+
+  static Future<void> save(Color primary, Color secondary) async {
+    final prefs = await SharedPreferences.getInstance();
+    await prefs.setInt(_key1, primary.value);
+    await prefs.setInt(_key2, secondary.value);
+  }
+}