dictionary CSSCalcDictionary {
  double? px = null;
  double? percent = null;
  double? em = null;
  double? ex = null;
  double? ch = null;
  double? rem = null;
  double? vw = null;
  double? vh = null;
  double? vmin = null;
  double? vmax = null;
  double? cm = null;
  double? mm = null;
  double? in = null;
  double? pc = null;
  double? pt = null;
};
