Remove rendering blocking resources.

I need help with removing rendering blocking resources. It is suggesting to Optimize CSS Delivery to

http://fonts.googleapis.com/css?family=Open+Sans%3A300italic%2C400%2C400italic%2C600%2C600italic%2C700%7CRoboto%3A300%2C400%2C400italic%2C500%2C500italic%2C700%2C900&ver=9.6.1