Red, White and Black

Are you wondering why the main colors are black, white & red?
Because that’s the three main colours in alchemy.

The nigredo, or blackness, or Œuvre au noir, represents the first stage of the process. It has no unique quality and may be, for the alchemist philosopher, the initial state of the materia prima (primordial matter). For those who work in the laboratory, it is the result of the decomposition of the elements. This decomposition is followed by a recomposition consisting of a union of the two feminine and masculine polarities. One might think the process is over, but this phase is itself followed by dissolution, the death of the product of the union, and a new nigredo. Everything here consists of deaths and resurrections!
The albedo or white dye or white stone or passage to white is the second stage.This moment of the process has two possible meanings. It can symbolize, writes Jung in Psychology and Alchemy (p.303):”The soul (anima) freed by death is again united with the dead body and determines its resurrection, or finally the set of colors (omnes colores or cauda pavonis, the tail of the peacock) leads to a single color, white which contains all colors.” This stage of the process already represents, for many alchemists, an achievement. It is symbolized by silver, or the moon, and Jung compares it to the dawn before sunrise. The transition to the ultimate stage, the rubedo, or red work.
It was done through the citrinitas (passage to yellow) associated with the sun and enlightenment. After the removal of this stage, the rubedo follows directly after the albedo. At this stage, red and white, the male sun and the female moon, can, as the fire reaches its peak, celebrate their chymic wedding.
This is all very simplified.

My own translation from that website

And of course, spirits, which are also ingredients that go through different stages, that mutate and transform, are also cousins of alchemy…
So such a website could only pay homage to this ancestral art, by adopting its colors.