X to Scalar and Z to Scalar need their input from Get position in Geometry, not from Y to Scalars Negate.
Get Normal in Geometry is supplying a 0-1 range of scalar data which represents X, Y, and Z axis. We use the convert X|Y|Z Scalars to separate this data to use individually.
I have to say though, with what you did do, you seemed to create a Y based gradient masking system for different colours, possibly useful for gas giants.