ConcaveGlassView.swift

struct ConcaveGlassView: ViewModifier {
    func body(content: Content) -> some View {
        if #available(iOS 15.0, *) {
            content
                .padding()
                .frame(height: 50)
                .background(.ultraThinMaterial)
                .overlay(
                    RoundedRectangle(cornerRadius: 14)
                        .stroke(.linearGradient(colors:[.black,.white.opacity(0.75)], startPoint: .top, endPoint: .bottom), lineWidth: 2)
                        .blur(radius: 2)
                )
                .overlay(
                    RoundedRectangle(cornerRadius: 14)
                        .stroke(.radialGradient(Gradient(colors: [.clear,.black.opacity(0.1)]), center: .bottomLeading, startRadius: 300, endRadius: 0), lineWidth: 15)
                        .offset(y: 5)
                )
                .cornerRadius(14)
        } else {
            // Fallback on earlier versions
            content
                .padding()
                .frame(height: 50)
                .cornerRadius(14)
                .shadow(color: .white, radius: 3, x: -3, y: -3)
                .shadow(color: .black, radius: 3, x: 3, y: 3)
        }
    }
}