diff --git a/src/main.cs b/src/main.cs
new file mode 100644
index 0000000..1f18e39
--- /dev/null
+++ b/src/main.cs
@@ -0,0 +1,26 @@
+using Godot;
+using System;
+
+public partial class main : Node2D
+{
+    // Called when the node enters the scene tree for the first time.
+    public override void _Ready()
+    {
+    }
+
+    // Called every frame. 'delta' is the elapsed time since the previous frame.
+    public override void _Process(double delta)
+    {
+        if (Input.IsActionJustPressed("hotkey_fullscreen"))
+        {
+            if (DisplayServer.WindowGetMode() == DisplayServer.WindowMode.Fullscreen)
+            {
+                DisplayServer.WindowSetMode(DisplayServer.WindowMode.Windowed);
+            }
+            else
+            {
+                DisplayServer.WindowSetMode(DisplayServer.WindowMode.Fullscreen);
+            }
+        }
+    }
+}