Applies a style to the area. When a style is applied - rather than set (see Area.SetStyle(Style) ) - only the differences between the new style and style properties previously assigned to the area (through the ExcelWriter API or in Microsoft Excel) will take effect. For example, if the area has a background color and the new style applied does not contain a background color, the area's color will not be affected. However, if the new style includes background color, it will replace the existing background color of the area.
styleA Style object representing the style to apply to the cell.