I'd suggest adding the support table for the column combinator

See https://www.w3.org/TR/selectors4/#column-combinator
with a warning :
The following features are at-risk and may be dropped during the CR period if there is not sufficient implementer interest: [...], the column combinator, [...]

Sample usage here (seems not supported) :
https://jsfiddle.net/oycycpsr/1/