Select how the fill color is applied to each chart element. You can choose between three Fill Mode options:

• Solid fill: The fill color will be applied without any additional effects. Default setting.
• Gradient to a derived color: A linear gradient will be applied to each chart element, using its fill color as one point and an automatically derived color variation as the other point. 
• Gradient to a single color: A linear gradient will be applied to each chart element, using its fill color as one point and a custom color as the other point.