[R] Help for funnel plot

[De Simone]

Hi,
Excuse me for this silly question
how do I get a colour gradient like the one attached. Colours are a bit
limited
Any specific code for the reference line and pseudo confidence lines. I use
"lty", but this do both

Here is my argument

dat <- escalc("MD", m1i=Mean_TAP, sd1i= SD_TAP, n1i= N_TAP,
m2i=Mean_caudal, sd2i= SD_caudal, n2i= N_caudal, slab=Study, data=
Duration_of_analgesia)



res <- rma(yi, vi, data=dat, measure="MD", method="DL")


funnel(res, main="Duration of analegsia", back = 12, xlab="Mean difference
(hours)", cex = 1.2,  lwd = 2, lty = "solid", mgp = c(2, 1, 0), font.main =
1, font.lab = 2, font.axis = 2)

Thank you