The board that answers

Build one interactive web page: A spirit board on a dark table, lit by three candles. Rest your fingers on the planchette and it follows them, a little late, like a heavy thing. Then ask it something. It leaves your fingers and spells the answer itself, while the pointer you are still moving carries on without it: you can see your own fingers part from it. Its lens magnifies the letter it is over, its shadow swings away from whichever flame is brightest, and the darkness is one layer with a hole cut for each flame. Asked where it is, it spells BEHIND YOU, the candle nearest you goes out and something knocks three times. Asked if you can stop, it says NO, the last flames go, and it slides towards you across the board in the dark.

Set it on an invented business called Sampleton, with its own drawn or generated pictures and no one else's files. It suits: A Halloween event, a ghost walk, a horror game or an escape room: anywhere a visitor has come to be unsettled and will take a minute over it. The taking away of control, shown in plain sight, suits any piece that wants to make the visitor feel something is not theirs. Do not let it fail the way this kind of piece usually does: A control that is taken and never given back, or a scare with no way out. Here it only overrules the planchette (the page and the pointer stay yours), it says so up front, never flashes, the knocks only sound if you turn sound on, and a button lights the candles again. Reduced motion stops the flicker and the tremor.

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.