OWASP ZAP when using spider showing in Spider tab "OUT OF CONTEXT" with url "weburl/Site.css"

I am new to OWASP ZAP and started manually testing through contexts and using Session Properties.

But I cannot able to detect all logged in url's of my huge website with the help of spider. Can anyone give me quick demo for how to detect all url's through spider by using proxy setting through firefox.

Waiting for your prompt reply!!

"CLICK FOR REFERENCE IMAGE"

Regards, Nisarg.