Major Emacs mode for editing Less files. Inspired by scss-mode.
(require 'less-mode)
(add-to-list 'auto-mode-alist '("\\.less$" . less-mode))
If you use smart-compile:
(add-to-list 'smart-compile-alist '(less-mode . (less-compile)))
If you use Flymake, it will work automatically.