Made the grid size adjustable (default is 12x12)

lib/main.dart

@@ -7,6 +7,7 @@ void main() {
 
 class MyApp extends StatelessWidget {
   const MyApp({super.key});
+  final int gridSize = 12;
 
   // This widget is the root of your application.
   @override
@@ -32,13 +33,13 @@ class MyApp extends StatelessWidget {
         colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
         useMaterial3: true,
       ),
-      home: const MyHomePage(title: 'Flutter Demo Home Page'),
+      home: const MyHomePage(title: 'Flutter Demo Home Page', gridSize: 12),
     );
   }
 }
 
 class MyHomePage extends StatefulWidget {
-  const MyHomePage({super.key, required this.title});
+  const MyHomePage({super.key, required this.title, required this.gridSize});
 
   // This widget is the home page of your application. It is stateful, meaning
   // that it has a State object (defined below) that contains fields that affect
@@ -50,15 +51,25 @@ class MyHomePage extends StatefulWidget {
   // always marked "final".
 
   final String title;
+  final int gridSize;
 
   @override
   State<MyHomePage> createState() => _MyHomePageState();
 }
 
 class _MyHomePageState extends State<MyHomePage> {
-  List<List<int>> _grid = List.generate(5, (_) => List.generate(5, (_) => Random().nextInt(5)));
+  late List<List<int>> _grid;
 
   @override
+  void initState() {
+    super.initState();
+    _initializeGrid();
+  }
+
+  void _initializeGrid() {
+    _grid = List.generate(widget.gridSize, (_) => List.generate(widget.gridSize, (_) => Random().nextInt(5)));
+  }
+
   Widget build(BuildContext context) {
     return Scaffold(
       appBar: AppBar(
@@ -68,16 +79,16 @@ class _MyHomePageState extends State<MyHomePage> {
         child: GridView.builder(
           shrinkWrap: true,
           gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
-            crossAxisCount: 5,
+            crossAxisCount: widget.gridSize,
           ),
-          itemCount: _grid.length * _grid.length,
+          itemCount: widget.gridSize * widget.gridSize,
           itemBuilder: (BuildContext context, int index) {
-            int row = index ~/ _grid.length;
-            int col = index % _grid.length;
+            int row = index ~/ widget.gridSize;
+            int col = index % widget.gridSize;
             return GestureDetector(
               onTap: () => _onTileTap(row, col),
               child: Container(
-                margin: EdgeInsets.all(4),
+                margin: EdgeInsets.all(2),
                 decoration: BoxDecoration(
                   color: _getColor(_grid[row][col]),
                   borderRadius: BorderRadius.circular(8),