A style can be set or applied to cells, rows, columns, ranges, and areas. When a style is set, it is cloned and the object to which the style is assigned acquires all of that style's properties, including font properties and number formatting. When a style is applied, only the differences between the new style and existing style properties (assigned through the ExcelWriter API or in Microsoft Excel) will take effect. For example, if the cell has a background color and the new style applied does not contain a background color, the cell's color will not be affected. However, if the new style includes a background color, it will replace the existing background color of the cell.