import UIKit

class SLNavigationViewController: UINavigationController {

}

class SLLoadingViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .systemYellow
    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)

        let nav = SLNavigationViewController()
        let mainView = StoreViewController()
        nav.navigationBar.frame.size = nav.navigationBar.sizeThatFits(CGSize(width: nav.navigationBar.frame.size.width, height: 2))
        nav.viewControllers = [mainView]

        present(nav, animated: false, completion: nil)

    }

}

class StoreViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .systemGreen
    }

}