CCI Line Gradient

//@version=5
indicator(title="CCI line gradient", precision=2, timeframe="")
var color GOLD_COLOR   = #CCCC00
var color VIOLET_COLOR = #AA00FF  
var color GREEN_BG_COLOR = color.new(color.green, 70)
var color RED_BG_COLOR   = color.new(color.maroon, 70)
float srcInput      = input.source(close, "Source")
int   lenInput      = input.int(20, "Length", minval = 5)
int   stepsInput    = input.int(50, "Gradient levels", minval = 1)
color bullColorInput   = input.color(GOLD_COLOR, "Line: Bull", inline = "11")
color bearColorInput   = input.color(VIOLET_COLOR, "Bear", inline = "11")
color bullBgColorInput = input.color(GREEN_BG_COLOR, "Background: Bull", inline = "12")
color bearBgColorInput = input.color(RED_BG_COLOR, "Bear", inline = "12")

// Plot colored signal line.
float signal = ta.cci(srcInput, lenInput)
color signalColor = color.from_gradient(signal, -200, 200, color.new(bearColorInput, 0), color.new(bullColorInput, 0))
plot(signal, "CCI", signalColor, 2)

// Detect crosses of the centerline.
bool signalX = ta.cross(signal, 0)
// Count no of bars since cross. Capping it to the no of steps from inputs.
int gradientStep = math.min(stepsInput, nz(ta.barssince(signalX)))
// Choose bull/bear end color for the gradient.
color endColor = signal > 0 ? bullBgColorInput : bearBgColorInput
// Get color from gradient going from no color to `c_endColor` 
color bandColor = color.from_gradient(gradientStep, 0, stepsInput, na, endColor)
bandTopPlotID = hline(100,  "Upper Band", color.silver, hline.style_dashed)
bandBotPlotID = hline(-100, "Lower Band", color.silver, hline.style_dashed)
fill(bandTopPlotID, bandBotPlotID, bandColor, title = "Band")