add css & style loader

src/index.tsx

@@ -1,9 +1,10 @@
 import * as React from "react";
 import * as ReactDOM from "react-dom";
-
 import Hello from "./components/Hello";
+import './index.css';
 
 ReactDOM.render(
   <Hello />,
+  // <div className="test">hello!!!!!</div>,
   document.getElementById('root') as HTMLElement
 );