Hello, I am trying to customize the crimson theme for our Scout website that I am updating.

https://peru-hummingbird-389022.hostingersite.com/index.php

This is a staging site, our live site uses the Casual theme and can be found here.

https://1stgodstone.org.uk/

How do I change the settings in the customization menu for mobile devices in the Crimson theme, to change the backgrounds in the below image from black to white or another colour, and is it possible to change the colour of the accordion type thing from red to purple. We have guidelines about branding and colours we can use from the Scout association, I would like to be able to follow these.

https://photos.app.goo.gl/UngjmNHgL4sVUaNp6