Lost Css Issue

I was looking to install an add-on for php live support chat and it required an add-on called CS-Cart Library – Underscore.js Utility Javascript. When I added the script it blew up my header. Uninstalling the script did not fix the issue. I have a second instance of the store running from backup files but I am not sure what I need to look at to fix the issue. The live store with the issue is https://www.ridetech.com/ and the backup is https://www.ridetech.com/dev

You can see the difference in the headers between the two. It looks like the live site is not pulling from the file main.css like the backup site is.

I have attached the add-on that seems to have caused this mess.

Not sure what I need to do to get the header back to looking like it should. Any help you be much appreciated

cs-cart-lib_underscore_js-1.0.0.zip

Did you clear the cache after you removed the *.js script(s)?