this is concerning the website www.gaelglobal.org please I need some help with editing the theme/CSS specifically, I am trying to remove this background picture from the theme

NotificationService.init();

FirebaseMessaging.instance.getInitialMessage().then((message) {
  if (message != null) {
    //code for navigation
  }
});

FirebaseMessaging.onMessage.listen((message) {
  if (message.notification != null) {
    print(message.notification!.title);
    print(message.notification!.body);
  }

  NotificationService.showNotification(message);
});

FirebaseMessaging.onMessageOpenedApp.listen((message) {
  //code for navigation
});