Setting Questions (Customizer)

Hi there.

I have some setting questions to be able amending some colour settings. Unfortunately I don't find the relevant sections for those settings:

1. I would like to change the main background colour of the whole site which is in B2B a dark grey. Where can I find the section for this change?
2. I would like to change the height of Slideshow headerbar and Headerbar which is both positioned in header. Where can I find the appropriate section?
3. I would like to change the article background colour which is positions in breadcrumb I believe. Where can I find this section?

Hope you can help me with this.

Many Thanks

Sven