public static function getActiveTheme()
    {
        if (self::$activeThemeCache !== false) {
            return self::$activeThemeCache;
        }

        $theme = static::load(static::getActiveThemeCode());

        if (!File::isDirectory($theme->getPath())) {
            return self::$activeThemeCache = null;
        }

        return self::$activeThemeCache = $theme;
    }