Default colours for pie chart

[Autio]

WaterAid suggested pie charts could default their first option to a green colour since most often they use pie charts for visualizing proportions of yes/no questions and most often yes is a good thing. Annie suggests we make the fix ourselves, but that we make the series' colour neutral to begin with, so that users don't end up with a stark red default for the option that should be green etc.

[grassick]

How do we want the colors to change? Here are the current ones... we can rearrange them as necessary:

Red and green are 3 and 4, and I'm worried about the default being ugly if we move them down. i.e. colors 5-8 are ugly.

Here are some alternate palettes:

https://nanx.me/ggsci/reference/pal_d3.html

https://carto.com/carto-colors/ (see categorical section)

[grassick]

Maybe switch to paired default? Check if affects existing charts. Make darker pair item first. https://github.com/d3/d3-scale-chromatic#schemePaired

[grassick]

Do not modify existing charts! Maybe have an easier picker for color scheme changes.

[grassick]

Initial tests show that colors appear to be stable, but needs more testing.