Thank you for the info! Just my thought:
– Yes, in my case, the CSS file was not loaded at all. It used to be work well, but then stop working suddenly. Changing the code (as previous message) get it works again.
– As it is deprecated, I think it is best to use the newest method that WordPress provides.
– If someone want to override CSS, they can simply put the CSS in the theme style.css, or any CSS file used by the current theme. Or there are many plugins that support custom CSS.
Just my opinion. Anyway I will keep using this plugin and thanks for that!