You can see the accordions and tabs on my test site.
At present I use the default colours for the accordion/tab headers. I would like to change them to the colours that I used with my plug-in which is no longer supported. I realise that I could set them for each individual accordion but, to give more flexibility, I would prefer to define the colours just once - in my child theme. I am not sure which classes (accordions-head, accordions-tab-head etc) I should refer to in the CSS.
Please feature "Header background color" only available in premium version.
Please see this screenshot where the option for icon color (also available in Free version)
Accordion content p tag css should used from your theme CSS although you can override by "!important"