feat: refactor financial wallet UI components and add offline map service support

lib/constant/finance_design_system.dart

@@ -0,0 +1,53 @@
+import 'package:flutter/material.dart';
+
+class FinanceDesignSystem {
+  // --- Colors ---
+  static const Color primaryDark = Color(0xFF0A0E21);
+  static const Color accentBlue = Color(0xFF3D5AFE);
+  static const Color successGreen = Color(0xFF00C853);
+  static const Color dangerRed = Color(0xFFD50000);
+  static const Color backgroundColor = Color(0xFFF6F8FA);
+  static const Color cardColor = Color(0xFFFFFFFF);
+  static const Color textSecondary = Color(0xFF757575);
+  static const Color textMuted = Color(0xFFBDBDBD);
+
+  // --- Gradients ---
+  static const LinearGradient balanceGradient = LinearGradient(
+    colors: [Color(0xFF0A0E21), Color(0xFF1A237E)],
+    begin: Alignment.topLeft,
+    end: Alignment.bottomRight,
+  );
+
+  static const LinearGradient dangerGradient = LinearGradient(
+    colors: [Color(0xFFD50000), Color(0xFFFF5252)],
+    begin: Alignment.topLeft,
+    end: Alignment.bottomRight,
+  );
+
+  // --- Radius ---
+  static const double mainRadius = 16.0;
+  static const double cardRadius = 20.0;
+  static const double buttonRadius = 12.0;
+
+  // --- Spacing ---
+  static const double horizontalPadding = 16.0;
+  static const double verticalSectionPadding = 24.0;
+
+  // --- Text Styles ---
+  static const TextStyle balanceStyle = TextStyle(
+    fontSize: 32,
+    fontWeight: FontWeight.bold,
+    color: Colors.white,
+  );
+
+  static const TextStyle headingStyle = TextStyle(
+    fontSize: 18,
+    fontWeight: FontWeight.bold,
+    color: primaryDark,
+  );
+
+  static const TextStyle subHeadingStyle = TextStyle(
+    fontSize: 14,
+    color: textSecondary,
+  );
+}