(customizr theme)How do i change the Logo and footer background colors

I’m trying to change the logo background color from white to black,as well as the footer background from white to black.I would like to also remove the gray strip above the footer entire as well if possible.Since I lack the css knowledge and full understanding of code,I was wondering if anyone out there could possibly help me out.There are other things I need help with,but these are the bigger issues that I currently have.