Textfield placeholder doesn't shows up well, SwitUI

Question

I'm trying to add login form to white color view but textfield placeholder can't see well, however on preview it shows up.

I tried to change placeholder color SwiftUI. How to change the placeholder color of the TextField? but it still doesn't shows up well. Could you give me some tip how can I solve this problem?

struct CardView: View {
    var body: some View {
        ZStack {
            Rectangle()
                .fill(Color(UIColor.white))
                .frame(height:300)
                .cornerRadius(10)
                .padding(16)
                 LoginForm()
        }
    }
}

struct LoginForm: View {
@State var username: String = ""
var body: some View {
        VStack(alignment:.center) {
        UsernameTextField(userNumber: $username)
            .padding(50)
        LoginButton()
    }.padding()
}

}

struct UsernameTextField: View {
@Binding var userNumber: String
var body: some View {
    TextField("Phone number", text: $userNumber)
        .padding(50)
        .onChange(of: userNumber, perform: { value in
            userNumber = formatNumberTextField(pattern: "+X(XXX) XXX XX XX", phoneNumber: userNumber)
        })
        .frame(height: 48)
        //.textFieldStyle(DefaultTextFieldStyle())
        .cornerRadius(16)
        .foregroundColor(.black)
        .accentColor(.black)
        .fixedSize(horizontal: true, vertical: false)
        .padding([.leading, .trailing], 10)
        .underlineTextField()
}