private function loadTheme()
    {
        if ($this->isThemeCacheValid()) {
            return;
        }
        $this->invalidateCache();

        $themeDir = $this->app['filesystem']->getDir('themes://' . $this->get('general/theme'));

        $this->data['theme'] = $this->parseTheme($themeDir, $this->data['general']);
    }