function CSSEscape(s) {
  // informed by https://github.com/mathiasbynens/mothereff.in/blob/master/css-escapes/eff.js
  var result = '';
  for (var i = 0; i < s.length; i += 1) 
    if (/[\t\r\n\v\f]/.test(s[i]))
      result += '\\' + s.charCodeAt(i).toString(16) + ' ';
    else if (/[ !"#$%&'()*+,./:;<=>?@\[\\\]^`{|}~]/.test(s[i]))
      result += '\\' + s[i];
    else
      result += s[i];
  if (/^\d/.test(result))
    result += '\\' + s.charCodeAt(0).toString(16) + ' ' + result.slice(1);
  return result;
}