gradation
Definitions
A series of successive changes, stages, or degrees in a particular order.
The act or process of arranging something in a series of gradual steps or stages.
A smooth, gradual transition from one color, tone, or shade to another.
Examples
The artist used a subtle gradation of colors to create a realistic sunset effect on the canvas.
There is a clear gradation in difficulty between the beginner and advanced levels of the course.