You can’t fill the area between series in a line chart, but it’s possible to achieve a similar effect using error bars.
- The error bars are colored with a gradient that replicates color encoding used for the series. A more neutral option could be used.
- Since it’s a gradient between two colors, you can remove the intermediate steps.
The error bars are calculated subtracting one series from the other. When imports are higher than exports this formula was used:
When exports are higher than imports: