add signin function

lib/pages/instruction.dart

@@ -1,4 +1,4 @@
-import 'package:fcs/theme/theme.dart';
+import 'package:fcs/fcs/common/theme.dart';
 import 'package:flutter/material.dart';
 import 'package:provider/provider.dart';
 import 'package:fcs/model/language_model.dart';
@@ -53,9 +53,10 @@ class _InstructionPageState extends State<InstructionPage> {
         ),
         body: Container(
           padding: EdgeInsets.only(left: 5, right: 5, top: 5),
-          child: Card(elevation: 0,
+          child: Card(
+              elevation: 0,
               child: Expanded(
-                              child: FittedBox(
+                child: FittedBox(
                     child: Image.asset(widget.image), fit: BoxFit.contain),
               )),
         ),