To be able to override the CSS properties of H5P activities, I need to modify some files in the theme (config.php, renderer.php, new css sheet within the styles folder). We use the Adaptable theme, which is a child theme of Boost. Since I am reluctant to make customizations directly in the theme, I would like to create a child theme of Adaptable. Is this possible at all?
If not, are there any other ways to customize files in the theme without running the risk of overwriting them when updating?
Edit: I'm using Moodle 3.9.1 and Adaptable 2.2.2