Usage: (require 'flymake-css) (add-hook 'css-mode-hook 'flymake-css-load) Beware that csslint is quite slow, so there can be a significant lag between editing and the highlighting of resulting errors. Like the author's many other flymake-*.el extensions, this code is designed to configure flymake in a buffer-local fashion, which avoids the dual pitfalls of 1) inflating the global list of `flymake-err-line-patterns' and 2) being required to specify the matching filename extensions (e.g. "*.css") redundantly. Based mainly on the author's flymake-jslint.el, and using the error regex from Arne Jørgensen's similar flymake-csslint.el. Uses flymake-easy, from https://github.com/purcell/flymake-easy