I would like to reuse the whole Casper Theme and just change one or two background colors. It seems to be overblown to copy the whole theme to just change two lines of CSS. Is there a way to extend an existing template with a new template? I don’t want to place or change files inside the main theme to keep it updateable.
Or do I need to upload a custom css file and load it manually in the header section of ghost (via injection in backend)?