reworked page layout inheritence

frontend/lib/main.dart

@@ -1,24 +1,27 @@
+import 'package:flutter/material.dart';
+
+import 'package:anyway/constants.dart';
 import 'package:anyway/utils/get_first_page.dart';
 import 'package:anyway/utils/load_trips.dart';
-import 'package:flutter/material.dart';
-import 'package:anyway/constants.dart';
+
 
 void main() => runApp(const App());
 
+// Some global variables
 final GlobalKey<ScaffoldMessengerState> rootScaffoldMessengerKey = GlobalKey<ScaffoldMessengerState>();
 final SavedTrips savedTrips = SavedTrips();
+// the list of saved trips is then populated implicitly by getFirstPage()
+
 
 class App extends StatelessWidget {
   const App({super.key});
 
 
   @override
-  Widget build(BuildContext context) {
-    return MaterialApp(
-      title: APP_NAME,
-      home: getFirstPage(),
-      theme: APP_THEME,
-      scaffoldMessengerKey: rootScaffoldMessengerKey
-    );
-  }
+  Widget build(BuildContext context) => MaterialApp(
+    title: APP_NAME,
+    home: getFirstPage(),
+    theme: APP_THEME,
+    scaffoldMessengerKey: rootScaffoldMessengerKey
+  );
 }