fixing landing page layout on server render

Summary:
On the first render the landing page was missing a CSS class. This ls probably related to https://github.com/gatsbyjs/gatsby/issues/5136
It is fixed by wrapping the page in a <div>

Reviewed By: priteshrnandgaonkar

Differential Revision: D8660801

fbshipit-source-id: dd1ac4145831f2556e2c7ceeaddb2a423447f833

website/src/components/Playground/index.js

@@ -19,6 +19,7 @@ import PositionRecord from './PositionRecord';
 import LayoutRecord from './LayoutRecord';
 import Sidebar from './Sidebar';
 import {Row, Col, Button} from 'antd';
+import btoa from 'btoa';
 import type {LayoutRecordT} from './LayoutRecord';
 import type {Yoga$Direction} from 'yoga-layout';
 import './index.css';

website/src/pages/index.js

@@ -183,12 +183,14 @@ const AboutSectionTwo = () => (
 );
 
 export default () => (
-  <Page className="landing-page" title="A cross-platform layout engine">
-    <HeroSection />
-    <PlaygroundSection />
-    <AboutSectionOne />
-    <hr />
-    <AboutSectionTwo />
-    <Footer />
-  </Page>
+  <div>
+    <Page className="landing-page" title="A cross-platform layout engine">
+      <HeroSection />
+      <PlaygroundSection />
+      <AboutSectionOne />
+      <hr />
+      <AboutSectionTwo />
+      <Footer />
+    </Page>
+  </div>
 );