inserida a fonte, e criada a tela de login_screen.dart

lib/widgets/buttom_custom.dart

@@ -0,0 +1,45 @@
+import 'package:flutter/material.dart';
+
+class ButtonCustom extends StatelessWidget{
+  final VoidCallback onPressed;
+  final String text;
+  final double size;
+  final Color colorButton;
+  final Color colorText;
+  final Color colorBorder;
+  final widthCustom;
+  final heightCustom;
+
+ButtonCustom({
+    required this.onPressed,
+    required this.text,
+    required this.size,
+    required this.colorButton,
+    required this.colorText,
+    required this.colorBorder,
+    this.widthCustom = 1.0,
+    this.heightCustom = 1.0
+});
+  @override
+  Widget build (BuildContext context) {
+    double width =MediaQuery.of(context).size.width;
+    double height =MediaQuery.of(context).size.height;
+
+    return ElevatedButton(
+      style: ElevatedButton.styleFrom(
+        primary: colorButton,
+        minimumSize: Size(width*widthCustom! , height*heightCustom!),
+        side:  BorderSide(width: 2,color : colorBorder,),
+      ),
+      onPressed: onPressed,
+      child: Text(text,
+        style: TextStyle(
+          color: colorText,
+          fontSize: size,
+            fontWeight: FontWeight.bold
+        ),
+      ) ,
+    );
+  }
+
+}