app.html

<!DOCTYPE html>
<html {{ HTML_ATTRS }}>
<link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/4.0.0-alpha.6/css/bootstrap.min.css">
<!-- <script src="https://use.fontawesome.com/5fff271fb5.js"></script> -->
<link href="//cdn.bootcss.com/font-awesome/4.7.0/css/font-awesome.min.css" rel="stylesheet">
  <!-- <link href="https://fonts.googleapis.com/css?family=Abel|Actor|Alegreya+Sans|Amiko|Antic|Archivo+Narrow|Assistant|Cabin|Cabin+Condensed|Catamaran|Chivo|Droid+Sans|Ek+Mukta|Hind|Josefin+Sans|Lato|Magra|Marvel|Maven+Pro|Molengo|Muli|Nunito|Nunito+Sans|Open+Sans|Oxygen|PT+Sans|Questrial|Quicksand|Raleway|Roboto|Source+Sans+Pro|Spinnaker:100,100i,200,200i,300,300i,400,400i,500,500i,600,600i,700,700i,800,800i,900,900i" rel="stylesheet"> -->
  <head>
    {{ HEAD }}
  </head>
  <body {{ BODY_ATTRS }}>
    {{ APP }}
  </body>
</html>