go with react-bootstrap for now

pages/_app.js

@@ -1,8 +1,9 @@
+import 'bootstrap/dist/css/bootstrap.min.css'
 import 'react-dates/lib/css/_datepicker.css'
 
 import moment from 'moment'
 import deLocale from 'moment/locale/de'
 
 export default function MyApp({ Component, pageProps }) {
-    return <Component {...pageProps} />
+  return <Component {...pageProps} />
 }