Programming ChartStyles
Also, see Changing ChartStyles
A ChartStyleobject defines the characteristics of a slice of a pie chart, a bar in a bar chart, or the points and lines in a plot, bubble, or radar chart. ChartStyles can be specified by series or by individual points. One ChartStyle object is defined for each series within a chart group, and for each point in a series. As new series or chart groups are added, new ChartStyle objects are automatically created by the chart.
Customizing ChartStyles