how to set background color with dynamic amount value

[clare]

hello experts

i am working with qlik sense enterprise 2021 May,  i want to define background color with below formula:

if(
percentage >Max(total percentage)*2/3, red(),
if(
percentage >Max(total percentage)/3, green(), blue()
) )

which you can see in picture 617, this is my purpose.

but i in my App this percentage keeps changing,   because i only have amount which keep changing , so i need calculate percentage like this:

(Sum(amount) - before(sum(amount)))/before(sum(amount))

and then put  (Sum(amount) - before(sum(amount)))/before(sum(amount))   into formula , but it not works

please help me on this question, how to realize picture 617 background color with dynamic amount value , thank you