code: function _compileAtrule(name) {
      var re = new RegExp('^@' + name + '\\s*([^;]+);');
      return function() {
        var pos = position();
        var m = match(re);
        if (!m) return;
        var ret = { type: name };
        ret[name] = m[1].trim();
        return pos(ret);
      }
    }
docs: Parse non-block at-rules