Inline small css – related posts

Google page speed is advisng this:

The following external resources have small response bodies. Inlining the response in HTML can reduce blocking of page rendering.

https://www.infolotnicze.pl/ should inline the following small resources:

https://www.infolotnicze.pl/wp-content/plugins/microkids-related-posts/microkids-related-posts-default.css

Any hints how to fix this?

http://ww.wp.xz.cn/extend/plugins/microkids-related-posts/