/* ============================================================
   PRISM — faces on a drum that turns forward one face at a time (27.10.2026)
   Used by: the /mcp hero pill (McpPills: Claude → Chat GPT → your AI tool) and the Birch MCP card in TwoWays
   (the AI client's logo). One rule for both, so the turn reads the same everywhere.

   <span class="prism" style="--prism-h: …"><span class="prism__face">…</span>…</span>
   The faces get their angle and the drum its count from site/src/lib/prism.ts (prism(el)); --prism-h is one face's
   height — the drum's radius is the apothem of the polygon: h / (2 · tan(180° / n)). The front face rests at z = 0,
   so there is no perspective zoom; the parent sets the perspective.
   ============================================================ */
.prism {
  --n: 3;
  --r: calc(var(--prism-h, 1em) / (2 * tan(180deg / var(--n))));
  position: absolute;
  inset: 0;
  transform-style: preserve-3d;
  transform: translateZ(calc(-1 * var(--r))) rotateX(var(--turn, 0deg));
  transition: transform 0.6s cubic-bezier(0.83, 0, 0.17, 1); /* a weighted quint, as live */
}
.prism__face {
  position: absolute;
  backface-visibility: hidden;
  transform: rotateX(var(--fx, 0deg)) translateZ(var(--r));
}
@media (prefers-reduced-motion: reduce) { .prism { transition: none; } }