private static function initStyles() {
            if (empty(self::$styles)) {
                foreach (self::$styleColours as $colourCode => $class) {
                    self::$styles[$colourCode] = new $class();

                    foreach (self::$styleVariants as $varCode => $var) {
                        self::$styles[$colourCode . $varCode] = new $class($var);
                    }
                }
            }
        }