Hi David,
Thank you very much for sending the spec.
I looked through the Charts section while working on my document.
My five cents. Take the comments for what they worth.

1. It seems that descriptions of Chart, XYChart, and LegendItem classes are missing, at least I couldn't find them.
2. It would be nice to have a simple example for each property, particular for ones that have several indexes, for example, chart-bar series<i> bar-legend-symbol default-color<j>
(I figured out how to apply them because I used the caspian file as a reference source.)
3. BarChart -no information about settings for negative bars (.negative.chart-bar {}).
4. LineChart - "chart-line-symblol series<i> default-color<j>" - typo in the word "symbol"
5. PieChart - "pie-legend-symbol <ith data item's style class>" - formatting problem
6. Axis, fx-tick-label-fill - seems wrong default value: 8 system. Requires Paint.

Regards,
Alla