made app modules movable in their order

lib/widget/placeholderView.dart

@@ -7,29 +7,26 @@ class PlaceholderView extends StatelessWidget {
   const PlaceholderView({super.key, required this.icon, required this.text, this.button});
 
   @override
-  Widget build(BuildContext context) => DefaultTextStyle(
-      style: const TextStyle(),
-      child: Center(
-        child: Container(
-          margin: const EdgeInsets.only(top: 100, left: 20, right: 20),
-          child: Column(
-            children: [
-              Container(
-                margin: const EdgeInsets.all(30),
-                child: Icon(icon, color: Colors.grey, size: 60),
-              ),
-              Text(text,
-                style: const TextStyle(
-                  fontSize: 20,
-                  color: Colors.grey,
-                ),
-                textAlign: TextAlign.center,
-              ),
-              const SizedBox(height: 30),
-              if(button != null) button!,
-            ],
-          ),
+  Widget build(BuildContext context) => Scaffold(
+    body: Center(
+      child: Container(
+        margin: const EdgeInsets.only(top: 100, left: 20, right: 20),
+        child: Column(
+          children: [
+            Container(
+              margin: const EdgeInsets.all(30),
+              child: Icon(icon, size: 60),
+            ),
+            Text(
+              text,
+              style: const TextStyle(fontSize: 20,),
+              textAlign: TextAlign.center,
+            ),
+            const SizedBox(height: 30),
+            if(button != null) button!,
+          ],
         ),
       ),
-    );
+    ),
+  );
 }