grunt uncss cannot seem to set the css path

Question

I have setup a uncss grunt task. my html files are in the 'public' folder my css ares in 'public/css'.

I setup my grunt task like so:

uncss: {
        dist: {
            files: {
                'faq.min.css' : ['public/faq.html']
            }
        }
    }

I get an error saying:

Fatal error: UnCSS: could not open /css

I do import my css like so in my html page:

    <link href="css/faq.min.css" rel="stylesheet" />

I've tried setting up htmlroot, csspath, but nothing seems to work.

if I set

csspath: 'css'

it adds an extra css to the path.

/homepage/public/css/css/faq.min.css

anyone can help?