No issue here, just wondering how it works under the hood.
If I use a theme with the following scss: (import statements not shown in preview, click through)
If I’m understanding your question (and I did click through ), it actually does come down to the template layout order — because, in the end, that’s still where the CSS/SCSS gets called. So if you want to override your theme, you’d call the preferred CSS/SCSS from a “higher” place in the layout order.
Since that was too simple, I’m probably not understanding your question. Sorry.
Both SCSS implementations (libsass and Dart Sass) has a concept of custom import resolvers, which allows Hugo to resolve imports against its union file system. If we don’t succeed, we will let “them” do it.