Cannot change styling [Plugin: cforms]

I have tried breaking this down in firebug, but no matter how I try I cannot get any of the different styles to work. If I paste the whole cforms css into my theme stylesheet it looks closer to the real deal, but things come out missing, such as no submit button.

Here is a link to the page in question:
https://www.isibusinessgroup.com/wordpress/?page_id=6

Here is a link to my theme stylesheet, as I have NOO idea what might be interfering:
https://www.isibusinessgroup.com/wordpress/wp-content/themes/black-minimalism-10/style.css

Please help. I love this plug-in and everything it has to offer.

Thanks.