This is only possible with CSS.
Add the following lines to your CSS and give your chart the id temperatureChart
.
#temperatureChart .series0.chart-series-area-fill {
-fx-fill: linear-gradient(to top, #0984df, #00d8ff 20%, #fff000 60%, #ff0000) ;
}
The right percent values you must figure out yourself.
Hope this helps,
Kalasch
EDIT(in code method):
To do this in Code, you can do the following(it is suggested that you check if the lookup is null):
sac.lookup("#temperatureChart .series0.chart-series-area-fill")
.setStyle("-fx-fill: linear-gradient(to top, #0984df, #00d8ff 20%, #fff000 60%, #ff0000);");
It is not recomended to do so, but if there is no other way...