import a .less file in theme

Hello there;

the theme for my telligent site is customized using .less files (css), I would like to create a base .less file that contais some global variables, and then imported in another .less file within the same theme.

I tried to use @import "-evo-themefile-url('mystyling.less')";  and @import "mystyling.less" at the top of my less file, but it does not seem to work.

any help on how to make this work?