How does one change pie chart wedge colors in Numbers for iOS?

I’m trying to change the colors of the wedges in this pie chart to arbitrary ones of my choosing, but I can’t figure out how to do this on iOS to save my life. The only option I can find is one to change the style of the entire chart, which randomly assigns each wedge to only the colors shown in the above screenshot.

I’ve tapped, double tapped, long pressed, and 3D touched every wedge and label, and searched through every level of every menu I can find and I don’t see this option anywhere. I know this is possible in the macOS version of Numbers, but I no longer own a Mac. Any help would be appreciated!