html.js

import React from 'react';
import DocumentTitle from 'react-document-title';

import { link } from 'gatsby-helpers';

module.exports = React.createClass({
 propTypes () {
    return {
      title: React.PropTypes.string,
    }
  },
  render () {
    let title = DocumentTitle.rewind()
    if (this.props.title) {
      title = this.props.title
    }

    let cssLink
    if (process.env.NODE_ENV === 'production') {
      cssLink = <link rel="stylesheet" href={link('/styles.css')} />
    }

    return (
      <html lang="en">
        <head>
          <meta charSet="utf-8"/>
          <meta httpEquiv="X-UA-Compatible" content="IE=edge"/>
          <meta name='viewport' content='user-scalable=no width=device-width, initial-scale=1.0 maximum-scale=1.0'/>
          <title>{title}</title>
          <link rel="shortcut icon" href={this.props.favicon}/>
        </head>
        <body className="landing-page">
          <div id="react-mount" dangerouslySetInnerHTML={{__html: this.props.body}} />
          <script src={link("/bundle.js")}/>
        </body>
      </html>
    );
  }
});