Grunt: Invalid CSS

[perguth]

git clone https://github.com/whiteout-io/mail-html5.git .
npm install
grunt --force

Yields

Syntax error: Invalid CSS after "    xs-only": expected ")", was ":             "..."
        on line 4 of src/sass/mixins/_responsive.scss
        from line 7 of src/sass/read-sandbox.scss
  Use --trace for backtrace.
Warning: Exited with error code 1 Used --force, continuing.
Syntax error: Invalid CSS after "    xs-only": expected ")", was ":             "..."
        on line 4 of src/sass/mixins/_responsive.scss
        from line 10 of src/sass/all.scss
  Use --trace for backtrace.
Warning: Exited with error code 1 Used --force, continuing.

and then hangs. Without --force it dies after the first error printing out Aborted due to warnings.

My machine runs: CentOS release 6.7 (Final)

[Abhayakara]

I don't know if you've figured this out yet, but the issue is that sass 3.2 won't parse that file. 3.3 does parse it happily. I'm working on ubuntu, so I had to "dpkg -r sass" and then "gem install sass" to fix the error.

[elviraux]

Did you install sass?