theme property
A collection of attributes for the button. The object takes SVG
attributes like fill, stroke, stroke-width or r, the
border radius. The theme also supports style, a collection of
CSS properties for the text. Equivalent attributes for the hover
state are given in theme.states.hover.
API Docs: https://api.highcharts.com/highcharts/chart.resetZoomButton.theme
Implementation
HighchartsChartResetZoomButtonThemeOptions? theme;