How to make a solid footer with all footer content in it

This is my site: https://doehrmann.com/wordpress/

This site is an example of the kind of footer I want: https://humaan.com

I want my social media icons, my credits, basically any text that is in the footer, to be in a solid dark piece at the bottom of the page. Like it is on the humaan.com site.
In my custom CSS (which I didn’t create but have taken over from the previous designer) I can change the color of different parts of footer but not all of it. Is there an easy way to do this?