Multiple child theme style sheets
I've made a child theme with style.css as it's only file (and used @import) and CSS additions I make to this file reflect on the site. A lot of changes I want to make are in blue.css, which I have activated. When I add these changes to my child style.css nothing happens. I have also tried an @import rule for blue.css - when I make changes to my child style.css subsequently they show as being cancelled out by the original blue.css.
I'm sure I'm making a simple error and any help gratefully received