Colors

Different elements, like column headers in the workbook can be highlighted with colors. Color is part of Formats. A color can be set as an RGB value or a colorname defined by Excel can be used.

See the complete reference: Color Reference

Examples

"rows": [{
    "values": [ "Title", "Firstname", "Lastname", "Birthday"],
    "format": {
        "fontSize": 13,
        "bold": true,
        "fontColor":{"name": "plum"}
        "backgroundColor": {"rgb": [180, 230, 255]}
	}
}]

Definitions

If a color is used in several formats, it can be defined at a central location and then be referenced from where it is used. That minimizes the effort to implement and update.