I’m not completely sure that I fully get what you are after, but does the following give, what you need?
seriescolor --> cgrad(:starrynight)
fillcolor --> get(palette(plotattributes[:seriescolor]), 0.1)
I’m not completely sure that I fully get what you are after, but does the following give, what you need?
seriescolor --> cgrad(:starrynight)
fillcolor --> get(palette(plotattributes[:seriescolor]), 0.1)