A dye vat that mixes

Build one interactive web page: Sampleton Dyeworks. The fusing-discs technique put to work: every disc is a dye, and discs that touch drift to the average colour of their group, weighted by area, and keep it when you pull them apart. A card names the biggest mixed group (Terracotta, Slate blue, Plum), gives its hex and lists what went into it. Pour them together, flick them apart, add a dye or rinse the vat.

Set it on an invented business called Sampleton, with its own drawn or generated pictures and no one else's files. It suits: A paint, dye, cosmetics, ink or textile brand, a colour-picker for a product, anywhere mixing is the idea. Do not let it fail the way this kind of piece usually does: A toy that implies a truth it does not have. Here the card states what it computes (an average by area, named to the nearest of twenty-two shades), every result is text as well as colour, and reduced motion keeps the discs still while dragging still mixes.

It must work with the keyboard, on a phone, with reduced motion respected and no text under 12px. Tell me which libraries you chose and why.