Render-blocking JavaScript and CSS

Vaadin 6 / 7 / 8
1

https://developers.google.com/speed/pagespeed/insights says:

Remove render-blocking JavaScript: VAADIN/vaadinPush.js?v=8.0.5 VAADIN/vaadinBootstrap.js?v=8.0.5 Optimize CSS Delivery of the following: themes/negdoortheme/styles.css?v=8.0.5 AppWidgetset/.../styles.css how can i resolve that?