feat: adopt material 3 theme and billing adjustments

lib/widgets/common/dialogs/confirmation_dialog.dart

@@ -1,4 +1,5 @@
 import 'package:flutter/material.dart';
+import '../../../theme/color_scheme_ext.dart';
 
 /// 확인 다이얼로그 위젯
 /// 사용자에게 중요한 작업을 확인받을 때 사용합니다.
@@ -99,7 +100,9 @@ class ConfirmationDialog extends StatelessWidget {
           ),
           child: Text(
             confirmText,
-            style: const TextStyle(color: Colors.white),
+            style: TextStyle(
+              color: Theme.of(context).colorScheme.onPrimary,
+            ),
           ),
         ),
       ],
@@ -164,12 +167,13 @@ class SuccessDialog extends StatelessWidget {
           Container(
             padding: const EdgeInsets.all(16),
             decoration: BoxDecoration(
-              color: Colors.green.withValues(alpha: 0.1),
+              color:
+                  Theme.of(context).colorScheme.success.withValues(alpha: 0.1),
               shape: BoxShape.circle,
             ),
-            child: const Icon(
+            child: Icon(
               Icons.check_circle,
-              color: Colors.green,
+              color: Theme.of(context).colorScheme.success,
               size: 64,
             ),
           ),
@@ -188,7 +192,7 @@ class SuccessDialog extends StatelessWidget {
               message!,
               style: TextStyle(
                 fontSize: 16,
-                color: Colors.grey[600],
+                color: Theme.of(context).colorScheme.onSurfaceVariant,
               ),
               textAlign: TextAlign.center,
             ),
@@ -203,7 +207,7 @@ class SuccessDialog extends StatelessWidget {
               onPressed?.call();
             },
             style: ElevatedButton.styleFrom(
-              backgroundColor: Colors.green,
+              backgroundColor: Theme.of(context).colorScheme.success,
               shape: RoundedRectangleBorder(
                 borderRadius: BorderRadius.circular(12),
               ),
@@ -214,8 +218,8 @@ class SuccessDialog extends StatelessWidget {
             ),
             child: Text(
               buttonText,
-              style: const TextStyle(
-                color: Colors.white,
+              style: TextStyle(
+                color: Theme.of(context).colorScheme.onPrimary,
                 fontSize: 16,
               ),
             ),
@@ -272,12 +276,12 @@ class ErrorDialog extends StatelessWidget {
           Container(
             padding: const EdgeInsets.all(16),
             decoration: BoxDecoration(
-              color: Colors.red.withValues(alpha: 0.1),
+              color: Theme.of(context).colorScheme.error.withValues(alpha: 0.1),
               shape: BoxShape.circle,
             ),
-            child: const Icon(
+            child: Icon(
               Icons.error_outline,
-              color: Colors.red,
+              color: Theme.of(context).colorScheme.error,
               size: 64,
             ),
           ),
@@ -296,7 +300,7 @@ class ErrorDialog extends StatelessWidget {
               message!,
               style: TextStyle(
                 fontSize: 16,
-                color: Colors.grey[600],
+                color: Theme.of(context).colorScheme.onSurfaceVariant,
               ),
               textAlign: TextAlign.center,
             ),
@@ -311,7 +315,7 @@ class ErrorDialog extends StatelessWidget {
               onPressed?.call();
             },
             style: ElevatedButton.styleFrom(
-              backgroundColor: Colors.red,
+              backgroundColor: Theme.of(context).colorScheme.error,
               shape: RoundedRectangleBorder(
                 borderRadius: BorderRadius.circular(12),
               ),
@@ -322,8 +326,8 @@ class ErrorDialog extends StatelessWidget {
             ),
             child: Text(
               buttonText,
-              style: const TextStyle(
-                color: Colors.white,
+              style: TextStyle(
+                color: Theme.of(context).colorScheme.onPrimary,
                 fontSize: 16,
               ),
             ),