toShadow = function toShadow(style) {
  if (typeof style !== "string") {
    return style;
  }

  return style.match(/([-.\d]+(?:%|ms|s|deg|cm|em|ch|ex|q|in|mm|pc|pt|px|vh|vw|vmin|vmax)?)|[%#A-Za-z0-9,.()]+/g);
}
@param string { string } - any valid CSS color value
@returns { string }