diff --git a/step1-04/demo/src/index.tsx b/step1-04/demo/src/index.tsx
index 5a97c2f..5c86c49 100644
--- a/step1-04/demo/src/index.tsx
+++ b/step1-04/demo/src/index.tsx
@@ -1,3 +1,4 @@
 import React from 'react';
 import ReactDOM from 'react-dom';
+
 ReactDOM.render(<p>hello world </p>, document.getElementById('app'));