I have been trying to use this with a mixin file, 'mixing.less' that I have stored in the Files section. If you pass a .css file name to the @import, it just passes the @import line through to the final css file. If the extension is omitted or is .less, the compiler does try to find the file, but fails. I tried adding portions of the path to the filename but I couldn't find a combination to work (i.e. Files/mixins.less,/Files/mixins.less, ../Files/mixins.less). Is there a syntax that will work for @import ?