How can idefer unused css in wordpress and uncaught reference error?

I always get a warning of uncaught reference and defer unused CSS, how can I overcome or resolve this my website is[enter link description here][1]

[1]: https://www.ekasya.com/ and these are the errors[enter image description here][1]

[1]: https://i.stack.imgur.com/128gm.png "I'm not pro in css much.