Sparkline styles

Sparkline styles control the colors of the various sparkline chart types.

Property Name	Data Type	Purpose
low-color	Selection	Defines the color of the lower value on a pie sparkline
medium-color	Selection	Defines the color for midrange values on a pie sparkline
high-color	Selection	Defines the color of the higher value on pie and bar sparklines
last-color	Selection	Defines the color of the last value in a series on a bar sparkline, and the line color on a line sparkline