The mix syntax is backwards from how I would have expected it to work. Maybe it's just me, which is why this is feedback rather than a bug, but when I read red | mix(color=base, amount=0.25) I would expect it to be 75% red and 25% base ("start with red, mix 0.25 of base in"), but it is actually the opposite (25% red, 75% base).

Might be too late to change it now, but I wanted to at least get my thoughts down that it was a bit confusing for me to use the first few times.