[Plugin: GigPress] CSS not loading

I’ve heard so many great things about this plugin and have tried installing it. My problem is that it does not seem to be loading the default css sheet. I have tried copying the default css and creating a new sheet titled gigpress.css in my main folder as suggested, but that still does not work.

I do have the <?php wp_head(); ?> in my theme’s header file, as I read this could be part of the problem. Any Ideas?

https://www.sleepcomesdown.com/wordpress/shows

https://www.ads-software.com/extend/plugins/gigpress/