Includes: @include
The include directive (@include) Copy the contents of a file into the current stylesheet instead of creating a reference like with @import. Unlike @import, there are no restrictions on where @include can be used, although the parent of a .@import rule must be a stylesheet (not a directive or style rule)
@include url(...);The url primitive is required. @import also accepts a second parameter, parse-only, which instructs the parser not to output the contents of the file. This is useful in cases where you want to load a file, copy portions of it or use variables/constants in it, but do not actually want the contents in the final output.
@include url(style_library.sss) parse-only;