class FirstViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    @IBAction func toDetail(_ sender: Any) {
        let controller = DetailViewController()
        controller.hidesBottomBarWhenPushed = true
        navigationController?.pushViewController(controller, animated: true)
    }

}

class DetailViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
        view.backgroundColor = .red
    }

}