public function build(string $bodyCssClass = self::DEFAULT_BODY_CSS_CLASS): string {
    $page          = $this->pageService->getCurrentPage();
    $backendLayout = $this->pageService->getBackendLayoutForPage($page['uid']);

    if (!empty($backendLayout)) {
      $bodyCssClass = "{$backendLayout} {$bodyCssClass}";
    }

    return '<body class="' . $bodyCssClass . '">';
  }