How do you change the main menu background colour?

CMS > Site options - ‘Theme’ tab - Elements - ‘Menu’ tab

[Background colour] Set the colour for the site main menu background here, using the drop down to select a colour from your site theme settings. 

[Text colour] Set the colour of the copy in the header here, using the drop down to select a colour from your site theme settings.  Consideration should be given to the background colour and contrast for WCAG purposes. 

[Active text colour] Use the drop down list to select the text colour of the section title when the section is ‘active’ i.e has been selected. Consideration should be given to the background colour and contrast for WCAG purposes.