added navigation to detail page

lib/pages/todo_detail_page.dart

@@ -1,11 +1,39 @@
 import 'package:flutter/material.dart';
 
+import '../models/todo.dart';
+import '../services/todo_provider.dart';
+
 class TodoDetailPage extends StatelessWidget {
   const TodoDetailPage({super.key});
+
   static const routeName = '/detail';
 
   @override
   Widget build(BuildContext context) {
-    return const Placeholder();
+    final Todo? todo = TodoProvider.selectedTodo;
+    if (todo == null) {
+      Navigator.of(context).pop();
+    }
+
+    final screenWidth = MediaQuery.of(context).size.width;
+    todo as Todo;
+
+    return Scaffold(
+      appBar: AppBar(),
+      body: Padding(
+        padding: EdgeInsets.symmetric(horizontal: screenWidth * 0.05),
+        child: Column(
+          children: [
+            Text(
+              todo.title,
+              style: Theme.of(context).textTheme.titleLarge,
+            ),
+            Text(
+              todo.description,
+            ),
+          ],
+        ),
+      ),
+    );
   }
 }