protected function csp(): array
    {
        if (! is_null($this->config['custom-csp'])) {
            if (empty($this->config['custom-csp'])) {
                return [];
            }

            return [
                'Content-Security-Policy' => $this->config['custom-csp'],
            ];
        }

        return Builder::getCSPHeader($this->config['csp']);
    }