Combi Diagramm - text shadow on datapoint labels

[Timo13]

Hey,

I would like to assign a text shadow to data point labels inside a combi diagramm for better readability.
How can I address them inside a .css? I managed to give a text shadow to quite everything but not the datapoint labels.

Here you see the text shadow in red. I can't seem to get it working.

Any hints, tips and help is appreciated!