Rename PageArea to MainArea

src/components/MainArea.js

@@ -1,7 +1,8 @@
-import './css/PageArea.css';
 import React, { Component } from 'react';
 
-class PageArea extends Component {
+import './css/MainArea.css';
+
+class MainArea extends Component {
     render() {
         return (
             <main>
@@ -11,4 +12,4 @@ class PageArea extends Component {
     }
 }
 
-export default PageArea;
+export default MainArea;