CssLint - Unexpected token

Question

I have this media query that, when parsed by CssLint, is giving an "unexpected token '321px'" error. Can anyone see why this is causing the error please? I can't. This is not being caused by the id selector. I've tested that by replacing it with a class selector and get the same error.

@media (max-width: 360px) and ( min-width: 321px) {
    #zoneSelectDiv {
      width: 180px;
    }
}