Tx! Brilliant site that manages to convey & implement colour aims well for practical use.
They also highlight issues with received wisdom on colour on the net—which is often not good.
[FYI, I own thousands of paintings by the artist Angela Weyersberg. To help promote her work on the net I had to employ a specialist in colour scanning to ensure on net they would roughly resemble the actual paintings.]
There are a lot of issues on net colours, mainly because they are still not fully standardised on hardware. It is an old problem. I thought https://stripe.com/blog/accessible-color-systems very good in it is trying to find a clearer way forward from the maze that is actual colour on screens.
[FYI, if you into commercial photo or movie production you have to have a calibrated screen—which cost thousands.]
Finally, palette making is likely still as much an art as a science ???
Passing thoughts, TT