Instagram app not displaying textfields and buttons

im trying to do an instagram app, so im doing the login screen. im doing it programmatically, but when i run the app the text fields and the button doesnt display.

class LoginViewController: UIViewController {

struct Constanst {
    static let cornerRadius: CGFloat = 0.0
}

private let usernameEmailField: UITextField = {
    let field = UITextField()
    field.placeholder = "Username or email"
    field.returnKeyType = .next
    field.leftViewMode = .always
    field.leftView = UIView(frame: CGRect(x: 0, y: 0, width: 10, height: 0))
    field.autocapitalizationType = .none
    field.autocorrectionType = .no
    field.layer.masksToBounds = true
    field.layer.cornerRadius = Constanst.cornerRadius
    field.backgroundColor = .secondarySystemBackground
    field.layer.borderWidth = 1.0
    field.layer.borderColor = UIColor.secondaryLabel.cgColor
    return field
}()

private let passwordField: UITextField = {
    let field = UITextField()
    field.isSecureTextEntry = true
    field.placeholder = "Password"
    field.returnKeyType = .continue
    field.leftViewMode = .always
    field.leftView = UIView(frame: CGRect(x: 0, y: 0, width: 10, height: 0))
    field.autocapitalizationType = .none
    field.autocorrectionType = .no
    field.layer.masksToBounds = true
    field.layer.cornerRadius = Constanst.cornerRadius
    field.backgroundColor = .secondarySystemBackground
    field.layer.borderWidth = 1.0
    field.layer.borderColor = UIColor.secondaryLabel.cgColor
    return field
    
}()

private let loginButton: UIButton = {
    let button = UIButton()
    button .setTitle("Log In", for: .normal)
    button.layer.masksToBounds = true
    button.layer.cornerRadius = Constanst.cornerRadius
    button.backgroundColor = .systemBlue
    button.setTitleColor(.white, for: .normal)
    return button
}()

private let termsButton: UIButton = {
    return UIButton()
}()

private let privacyButton: UIButton = {
    return UIButton()
}()

private let createAccountButton: UIButton = {
    let button = UIButton()
    button.setTitleColor(.label, for: .normal)
    button.setTitle("New User? Create an account", for: .normal)
    return button
}()

private let headerView: UIView = {
    let header = UIView()
    header.clipsToBounds = true
    let backgroundView = UIImageView(image: UIImage(named: "gradient"))
    header.addSubview(backgroundView)
    return header
}()


override func viewDidLoad() {
    super.viewDidLoad()
    usernameEmailField.delegate = self
    passwordField.delegate = self
    addSubviews()
    view.backgroundColor = .systemBackground
}

override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()
    
    // Assign frames
    headerView.frame = CGRect(
        x: 0,
        y: 0.0,
        width: view.width,
        height: view.height/3.0)
    
    usernameEmailField.frame = CGRect(
        x: 25.0,
        y: headerView.bottom + 10.0,
        width: view.width-50,
        height: 52.0)
    
    passwordField.frame = CGRect(
        x: 25,
        y: usernameEmailField.bottom + 10,
        width: view.width-50,
        height: 52.0)
    
    loginButton.frame = CGRect(
        x: 25,
        y: passwordField.bottom + 10,
        width: view.width-50,
        height: 52.0)
    
    createAccountButton.frame = CGRect(
        x: 25,
        y: loginButton.bottom+10,
        width: view.width-50,
        height: 52.0)
    
    configureHeaderView()
}

private func configureHeaderView() {
    guard headerView.subviews.count == 1 else {
        return
    }
    guard let backgroundView = headerView.subviews.first else {
        return
    }
    backgroundView.frame = headerView.bounds
    
    // Add instagram logo

    let imageView = UIImageView(image: UIImage(named: "text"))
    headerView.addSubview(imageView)
    imageView.contentMode = .scaleAspectFit
    imageView.frame = CGRect(x: headerView.width / 4.0,
                             y: view.safeAreaInsets.top,
                             width: headerView.width / 2.0,
                             height: headerView.height - view.safeAreaInsets.top)
}

private func addSubviews() {
    view.addSubview(usernameEmailField)
    view.addSubview(passwordField)
    view.addSubview(loginButton)
    view.addSubview(termsButton)
    view.addSubview(privacyButton)
    view.addSubview(createAccountButton)
    view.addSubview(headerView)
}

@objc private func didTapLoginButton(){
    
}
@objc private func didTapTermsButotn() {
    
}
@objc private func didTapPrivacyButton() {
    
}
@objc private func didTapCreateAccountButton() {
    
}

}

extension LoginViewController: UITextFieldDelegate {
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
if textField == usernameEmailField {
passwordField.becomeFirstResponder()
}
else if textField == passwordField {
didTapLoginButton()
}
return true
}
}