<===> input.scss
div {
  span, p, span {
    color: red;
  }
  a.foo.bar.foo {
    color: green;
  }
  &:nth(-3) {
    color: blue;
  }
}

@-webkit-keyframes {
  from {
    left: 0px;
    10% {
      whatever: hoo;
    }
  }
  to {
    left: 200px;
  }
}

div {
  @whatever {
    blah: blah;
    stuff {
      blah: bloh;
    }
  }
}


a, b {
  color: red;
  c, d {
    height: 10px;
    e, f {
      width: 12px;
    }
  }
}

<===> output.css
div span, div p, div span {
  color: red;
}
div a.foo.bar.foo {
  color: green;
}
div:nth(-3) {
  color: blue;
}

@-webkit-keyframes {
  from {
    left: 0px;
    10% {
      whatever: hoo;
    }
  }
  to {
    left: 200px;
  }
}
@whatever {
  div {
    blah: blah;
  }
  div stuff {
    blah: bloh;
  }
}
a, b {
  color: red;
}
a c, a d, b c, b d {
  height: 10px;
}
a c e, a c f, a d e, a d f, b c e, b c f, b d e, b d f {
  width: 12px;
}