code: function quotesRequired(family) {
    return family.split(/\s+/).some(word => {
      return (
        /^(-?\d|--)/.test(word) ||
        !/^[-_a-zA-Z0-9\u{00A0}-\u{10FFFF}]+$/u.test(word)
      );
    });
  }
docs: Quotes are required if the family is not a valid CSS identifier (regexes from https://mathiasbynens.be/notes/unquoted-font-family)