I think the instructions for this challenge are a little unhelpful and are just confusing to people that are new to it. Hopefully this will help to clarify it:
90deg, // gradient angle
yellow 0px, // color stop 1
blue 40px, // color stop 2
green 40px, // color stop 3
red 80px // color stop 4
In order to complete the challenge, you only need to change five things and the syntax stays the same.
The instructions are really getting at how the blending works, which I recommend you experiment with in order to understand it. If you take a look at color stops 2 and 3, you will see that they are both set to 40px- this means that there will be no blending between the blue and green. color stops 3 and 4 are set to different values of px’s and so there is a blending of red and green.
I hope this makes sense and is of some help
PS: if you are still stuck, see what happens when you change the colors