Type of expression is ambiguous without more context error SwiftUI

I made a Neumorphic-style view with a title and a neumorphic button. The view changes when I turn on dark mode in the preview code. I then decided to make a toggle that'll switch dark mode on or off. I unfortunately haven't found a way to give the toggle its functionality (but it shouldn't be creating any errors), and I get this error. I have a whole struct for the Neumorphic style before, which is why you might see terms you don't know. When I remove the toggle, the error disappears.

struct ContentView: View {

    @Environment(\.colorScheme) private var colorScheme
    @State private var isToggle : Bool = false

    var body: some View {

        ZStack {
            VStack {

                Text("Neumorphism") <- Type of expression is ambiguous without more context
                    .font(.system(size: 32,
                                  weight: .bold,
                                  design: .rounded))

                Button("Hello world", action: { })

            .frame(minWidth: 0, maxWidth: .infinity,
                   minHeight: 0, maxHeight: .infinity,
                   alignment: .center)
                .buttonStyle(NeumorphicButtonStyle(colorScheme: colorScheme))

            Toggle(isOn: $isToggle) {
                 Text("Dark Mode") <- How could I make this turn on and off dark mode?


    var backgroundColor: Color {
        switch colorScheme {
        case .light: return NeumorphicButtonStyle.Appearance().lightColor
        case .dark: return NeumorphicButtonStyle.Appearance().darkColor
        @unknown default: return NeumorphicButtonStyle.Appearance().lightColor
struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
            .environment(\.colorScheme, .light)