activeDataLabelStyle property
Additional styles to apply to the data label of a point that has drilldown data. By default it is underlined and blue to invite to interaction.
In styled mode, active data label styles can be applied with the
.highcharts-drilldown-data-label
class.
API Docs: https://api.highcharts.com/highcharts/drilldown.activeDataLabelStyle
Implementation
HighchartsDrilldownActiveDataLabelStyleOptions? activeDataLabelStyle;