Playground issue

Hi, I'm just starting out and I'm trying to learn Swift with various tools including the Playground and I'm doing the "continue with the apps" exercises. I'm stuck at the point where I need to add the Colorpicker to change the color. The code seems right but the app won't let me move forward.

struct CreatureDetail: View { /#-code-walkthrough(creatureDetail.intro)/ /#-code-walkthrough(creatureDetail.creatureConstant)/ let creature : Creature /#-code-walkthrough(creatureDetail.creatureConstant)/

//#-learning-code-snippet(addStateVarIsScaled)
/*#-code-walkthrough(creatureDetail.stateVars)*/
@State var color = Color.white
@State var shadowRadius : CGFloat = 0.5
@State var angle = Angle(degrees: 0)
/*#-code-walkthrough(creatureDetail.stateVars)*/

var body: some View {
    VStack {
        Text(creature.emoji)
            .resizableFont()
            .colorMultiply(color)
            .shadow(color: color, radius: shadowRadius * 40)
            .rotation3DEffect(angle, axis: (x: 0.0, y: 1.0, z: 0.0))
        
        ColorPicker("Choose a Color", selection: $color) 
            .padding(.horizontal)
    }
}

}