design: Nicer first loading design

assets/l10n/intl_en.arb

@@ -1233,6 +1233,11 @@
     "type": "text",
     "placeholders": {}
   },
+  "yourChatsAreBeingSynced": "Your chats are being synced...",
+  "@yourChatsAreBeingSynced": {
+    "type": "text",
+    "placeholders": {}
+  },
   "pleaseChoose": "Please choose",
   "@pleaseChoose": {
     "type": "text",

lib/pages/views/chat_list_view.dart

@@ -214,7 +214,20 @@ class ChatListView extends StatelessWidget {
                                 );
                               } else {
                                 return Center(
-                                  child: CircularProgressIndicator(),
+                                  child: Column(
+                                    mainAxisSize: MainAxisSize.min,
+                                    children: [
+                                      Image.asset(
+                                        'assets/private_chat_wallpaper.png',
+                                        width: 100,
+                                      ),
+                                      Text(
+                                        L10n.of(context)
+                                            .yourChatsAreBeingSynced,
+                                        textAlign: TextAlign.center,
+                                      ),
+                                    ],
+                                  ),
                                 );
                               }
                             },

lib/pages/views/new_group_view.dart

@@ -40,7 +40,7 @@ class NewGroupView extends StatelessWidget {
               onChanged: controller.setPublicGroup,
             ),
             Expanded(
-              child: Image.asset('assets/new_group_wallpaper.png'),
+              child: Image.asset('assets/private_chat_wallpaper.png'),
             ),
           ],
         ),

lib/widgets/connection_status_header.dart

@@ -48,10 +48,11 @@ class _ConnectionStatusHeaderState extends State<ConnectionStatusHeader> {
         );
 
     return AnimatedContainer(
-      duration: Duration(milliseconds: 300),
+      duration: Duration(milliseconds: 250),
+      curve: Curves.bounceInOut,
       height: _connected ? 0 : 36,
       clipBehavior: Clip.hardEdge,
-      decoration: BoxDecoration(),
+      decoration: BoxDecoration(color: Theme.of(context).secondaryHeaderColor),
       padding: EdgeInsets.symmetric(horizontal: 12),
       child: Row(
         mainAxisAlignment: MainAxisAlignment.center,