Hi,
I want't to change the color of all pages to black. But I can not firnd a control in customizer to do this.

Thats not possible.
You can setup only the site background to black.
If you want to setup your complete site to black you have to customize the complete CSS files, because you have to set all
text colors, list colors and many more styles to white!

Analyze the site with Firebug and then copy this code to your css / custom.css with modified colors and background colors.

Thanks for your reply,
I have been learning about CSS sheets as I have not had any previous experience, so I could use a little more help.

I mainly want to change the home page to black with contrasting text. I have looked at the CSS sheets with Firebug but I am unable to determine the relevant elements as the code is more complex than I am used to.

Are you able to point me in the right direction?

Thanks in advance

We are committed to help you with any type of support query, however we can't provide extensive help in terms of customizations. In general customizations may look simple but you will require solid knowledge of web technologies and programming skills to do them or hire a professional who can do it for you.