Series.Heatmap - Using the Heatmap Label Style Element

The Heatmap Label Style element can be used to control the appearance of the label text that displayed inside the cells:

By default, labels will appear at the top of the cell, as shown above, top. The Heatmap Label Style element has attributes that allow you to control the font family, color, size, and weight, and positioning of the text. You can also specify different font colors for cells with light and dark backgrounds.