Perfect, Thanks, Bikhu.
My understanding is, that the disc has one color. The disk is created out of fragments.
If the fragments become scaled, you like to have two colors:
the part that goes to one side, becomes one color and
the part that goes down, the other color.
To do that, I created a gradient. This Gradient Shader is set to None, so I have three colors: disc, up and down parts
The projection (Texture Tag) is set to flat, so the Gradient while set to V works vertical. Can you see the yellow grid, this is the representation of the Flat projection, while in Texture Mode [left side in the menu]
Note that the projection and the position of the sliders [gradient] working here dependent (visually only) to get this result. If you change one, the other one needs adjustment.
Move the Plain Effector and you can see it. Change the colors to the one you need, mine are set for demonstration purposes and not based on taste.
All the best