if you want to have to separate files for CSS.. something that in general not recommended since browsers are caching it and it's not a big deal.. but either case hacing them in different supercategories doesn't make since you could simply do that:

    STYLES = ['src/style/style.less', 'src/style/ckeditor.less']

and the order remains..

but if you are going to include these two files always in all pages then just import it using LESS.. otherwise do the above with the simple array and load the second entry only in specific pages by modifying the style.html :)