Reworking static page generation

Including styles in components wasn't working with the old system.

src/components/App.js

@@ -1,15 +1,11 @@
 import React from 'react';
 
-import Header from './Header';
-import Footer from './Footer';
 import Message from './Message';
 
-const App = () => <React.Fragment>
-  <Header/>
+const App = () => (
   <Message heading="React App">
     <p>Placeholder app content</p>
   </Message>
-  <Footer/>
-</React.Fragment>;
+);
 
 export default App;