Step 3a: switch to CSS modules

Everybody loves CSS modules, and the great news is that they come free with Webpack.
The bad news is that we can't use them with server-side rendering, as we don't use
Webpack when rendering on the server-side.
So at this step we broke everything, and the only way to continue from here, is to
start using Webpack to pre-build code for server-side rendering too, and that's
what we'll do at the next step.

Hello.js

@@ -1,11 +1,9 @@
 import React from 'react';
-if (process.env.BROWSER) {
-    require('Hello.css');
-}
+import s from 'Hello.scss';
 
 const Hello = React.createClass({
   render: function() {
-    return <div className="Hello">Hello {this.props.name}</div>;
+    return <div className={s.root}>Hello {this.props.name}</div>;
   }
 });
 

Hello.css → Hello.scss

@@ -1,4 +1,4 @@
-.Hello {
+.root {
     font-size: 3em;
     font-family: sans-serif;
     color: rebeccapurple;