seriesGroupShadow property
Whether to apply a drop shadow to the global series group. This causes
all the series to have the same shadow. Contrary to the series.shadow
option, this prevents items from casting shadows on each other, like for
others series in a stack. The shadow can be an object configuration
containing color, offsetX, offsetY, opacity and width.
API Docs: https://api.highcharts.com/highcharts/chart.seriesGroupShadow
Implementation
Map<String, dynamic>? seriesGroupShadow;