Add Charset to css and js files

I noticed that my css and js files were being served without the charset in the content type…

content-type: text/css;

It should be (source)…

content-type: text/css; charset=utf-8

To resolve, login to Plesk and navigate to your domain, and click Apache & nginx Settings, scroll down to Additional nginx directives and add…

as you can see, you can just list the file types as you would for gzip_types.