我希望 FIRST FALL-ABOVE 蜡烛和 FIRST GROW-BELOW 蜡烛具有突出显示的背景，其中 Fall Above 为石灰，Grow below 为红色。我怎么能只在第一根蜡烛上获得背景亮点？
如何在这些蜡烛上创建警报条件？任何帮助将不胜感激。类似于以下内容，然后是 MACD 代码本身。
//Alert condition and first growth and first shrunk candle marked
peak = bcolor == green and bcolor[1] == lime
trough = bcolor == maroon and bcolor[1] == red
bgcolor(color = peak ? lime : trough ? red : na)
alertcondition(peak, "Peak Top", "Top Peak (short)")
alertcondition(trough, "Trough Bottom", "Bottom Trough (long)")
//MACD
study(title="MACD", shorttitle="MACD", resolution="")
fast_length = input(title="Fast Length", type=input.integer, defval=12)
slow_length = input(title="Slow Length", type=input.integer, defval=26)
src = input(title="Source", type=input.source, defval=close)
signal_length = input(title="Signal Smoothing", type=input.integer, minval = 1, maxval = 50,
defval = 9)
sma_source = input(title="Simple MA (Oscillator)", type=input.bool, defval=false)
sma_signal = input(title="Simple MA (Signal Line)", type=input.bool, defval=false)
// colors
col_grow_above = #26A69A
col_grow_below = #FFCDD2
col_fall_above = #B2DFDB
col_fall_below = #EF5350
col_macd = #0094ff
col_signal = #ff6a00
// Calculation
fast_ma = sma_source ? sma(src, fast_length) : ema(src, fast_length)
slow_ma = sma_source ? sma(src, slow_length) : ema(src, slow_length)
macd = fast_ma - slow_ma
signal = sma_signal ? sma(macd, signal_length) : ema(macd, signal_length)
hist = macd - signal
plot(hist, title="Histogram", style=plot.style_columns, color=(hist>=0 ? (hist[1] < hist ?
col_grow_above : col_fall_above) : (hist[1] < hist ? col_grow_below : col_fall_below) ),
transp=0 )
plot(macd, title="MACD", color=col_macd, transp=0)
plot(signal, title="Signal", color=col_signal, transp=0)