Changed Font and Theme

lib/theme.dart

@@ -0,0 +1,10 @@
+import 'package:flutter/material.dart';
+
+ThemeData get darkTheme => ThemeData(
+      colorScheme: ColorScheme.fromSeed(
+        seedColor: const Color(0xAAbb71fc),
+        brightness: Brightness.dark,
+      ),
+      useMaterial3: true,
+      fontFamily: 'SourceSerif4',
+    );