Have you tried naming the file application.css.scss?
You can include specific style sheets by deleting the ‘require tree’ comment from the application stylesheet and then using @import “example.css.scss”; for every stylesheet that you have. Doing this means you can specify the order in which they compile.
Yeah, I am using the @import now. I was expect it to be automatic, but I guess the logic is that if you are using sass for the layout then you will want complete control of how things are brought in.