CSSlint, our current recommendation, is limited to some basic linting. It doesn't do advanced linting like "only use features that are compatible with IE6+" or whatever. It doesn't do any style checking (e.g. consistent ordering of attributes), and hasn't had a release in over two years (August 2013).
There are some possible replacements (stylelint most obviously), but we should work out what we think is best and just do it.