diff --git a/src/systems/DialogueSystem.js b/src/systems/DialogueSystem.js
index f408384..89f6096 100644
--- a/src/systems/DialogueSystem.js
+++ b/src/systems/DialogueSystem.js
@@ -15,7 +15,7 @@
  * @date 2025-12-23
  */
 
-export default class DialogueSystem {
+class DialogueSystem {
     constructor(scene) {
         this.scene = scene;
 
diff --git a/src/systems/TwinBondSystem.js b/src/systems/TwinBondSystem.js
index 74f200e..fb7fd64 100644
--- a/src/systems/TwinBondSystem.js
+++ b/src/systems/TwinBondSystem.js
@@ -23,7 +23,7 @@
  * @date 2025-12-23
  */
 
-export default class TwinBondSystem {
+class TwinBondSystem {
     constructor(scene) {
         this.scene = scene;