Not child-theme friendly?

So if I create a child theme, select the child theme in Themes and make sure it’s active, any customization I do to a child theme copy of themes/discovery-child/css/<insert color here>.css is not reflected on the site and the main theme’s version of that file is used instead.

Is there no way to make it conform to child theme rules for these files or do I just need to continue using a version of the theme before these new selectable colors were added?