changed primary color usage to fix the color bug in dark mode

Changed Theme.of(context).primaryColor to Theme.of(contex).colorScheme.primary to make dark mode work properly.

lib/features/dashboard/widgets/account_card.dart

@@ -13,7 +13,7 @@ class AccountCard extends StatelessWidget {
       width: 300,
       padding: const EdgeInsets.all(20),
       decoration: BoxDecoration(
-        color: Theme.of(context).colorScheme.onPrimary,
+        color: Colors.white,
         borderRadius: BorderRadius.circular(12),
         boxShadow: [
           BoxShadow(
@@ -33,7 +33,7 @@ class AccountCard extends StatelessWidget {
               Text(
                 account.accountType,
                 style: TextStyle(
-                  color: Theme.of(context).scaffoldBackgroundColor,
+                  color: Theme.of(context).colorScheme.onPrimary,
                   fontSize: 18,
                   fontWeight: FontWeight.bold,
                 ),
@@ -42,7 +42,7 @@ class AccountCard extends StatelessWidget {
                 account.accountType == 'Savings'
                     ? Icons.savings
                     : Icons.account_balance,
-                color: Theme.of(context).scaffoldBackgroundColor,
+                color: Theme.of(context).colorScheme.onPrimary,
               ),
             ],
           ),
@@ -50,13 +50,13 @@ class AccountCard extends StatelessWidget {
           Text(
             account.accountNumber,
             style: TextStyle(
-                color: Theme.of(context).scaffoldBackgroundColor, fontSize: 16),
+                color: Theme.of(context).colorScheme.onPrimary, fontSize: 16),
           ),
           const SizedBox(height: 30),
           Text(
             '${account.currency} ${account.balance.toStringAsFixed(2)}',
             style: TextStyle(
-              color: Theme.of(context).scaffoldBackgroundColor,
+              color: Theme.of(context).colorScheme.onPrimary,
               fontSize: 22,
               fontWeight: FontWeight.bold,
             ),
@@ -65,10 +65,11 @@ class AccountCard extends StatelessWidget {
           Text(
             AppLocalizations.of(context).availableBalance,
             style: TextStyle(
-                color: Theme.of(context).scaffoldBackgroundColor, fontSize: 16),
+                color: Theme.of(context).colorScheme.onPrimary, fontSize: 16),
           ),
         ],
       ),
     );
   }
 }
+