:root {
  --bg-0: #030304;
  --bg-1: #0a0b0e;
  --steel-400: #6b7280;
  --steel-600: #3a3f47;
  --ember: 255, 176, 102;
  --credit-color: #5a5f68;
}

* {
  box-sizing: border-box;
}

html, body {
  height: 100%;
  margin: 0;
}

body {
  background: var(--bg-0);
  color: var(--credit-color);
  display: grid;
  grid-template-rows: 1fr auto;
  height: 100dvh;
  width: 100%;
  overflow: hidden;
  position: relative;
  isolation: isolate;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ---------- Background scene ---------- */

.scene {
  position: fixed;
  inset: 0;
  z-index: 0;
  background:
    radial-gradient(ellipse at 50% 42%, var(--bg-1) 0%, var(--bg-0) 62%, #000000 100%);
}

.scene::before {
  /* faint etched circuit grid */
  content: "";
  position: absolute;
  inset: -10%;
  opacity: 0.05;
  mix-blend-mode: screen;
  background-image:
    linear-gradient(rgba(120, 140, 160, 0.6) 1px, transparent 1px),
    linear-gradient(90deg, rgba(120, 140, 160, 0.6) 1px, transparent 1px);
  background-size: 64px 64px;
  animation: driftGrid 90s linear infinite;
}

.scene::after {
  /* vignette */
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at 50% 45%, transparent 38%, rgba(0, 0, 0, 0.65) 100%);
}

.grain {
  position: fixed;
  inset: 0;
  z-index: 1;
  opacity: 0.05;
  mix-blend-mode: overlay;
  pointer-events: none;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='180' height='180'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/></filter><rect width='100%25' height='100%25' filter='url(%23n)'/></svg>");
  background-size: 180px 180px;
}

@keyframes driftGrid {
  from { background-position: 0 0, 0 0; }
  to { background-position: 128px 64px, 64px 128px; }
}

/* ---------- Vault stage ---------- */

.stage {
  position: relative;
  z-index: 2;
  display: grid;
  place-items: center;
  perspective: 1200px;
  min-height: 0;
  min-width: 0;
  overflow: hidden;
}

.spotlight {
  position: absolute;
  width: min(90vw, 90vh);
  height: min(90vw, 90vh);
  border-radius: 50%;
  background: radial-gradient(circle, rgba(var(--ember), 0.16) 0%, rgba(var(--ember), 0.05) 32%, transparent 68%);
  filter: blur(6px);
  animation: breathe 7s ease-in-out infinite;
  pointer-events: none;
}

@keyframes breathe {
  0%, 100% { transform: scale(0.94); opacity: 0.75; }
  50% { transform: scale(1.04); opacity: 1; }
}

.vault-rings {
  position: absolute;
  width: min(78vw, 78vh);
  height: min(78vw, 78vh);
  border-radius: 50%;
  pointer-events: none;
}

.vault-rings::before,
.vault-rings::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: 50%;
  border: 1px solid rgba(107, 114, 128, 0.16);
}

.vault-rings::after {
  inset: 8%;
  border-color: rgba(107, 114, 128, 0.1);
  animation: rotateSlow 140s linear infinite reverse;
}

.vault-rings::before {
  animation: rotateSlow 200s linear infinite;
}

@keyframes rotateSlow {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

/* ---------- Emblem ---------- */

.emblem-wrap {
  position: relative;
  z-index: 2;
  transform: rotateX(var(--tilt-y, 0deg)) rotateY(var(--tilt-x, 0deg));
  transition: transform 0.4s ease-out;
  animation: float 9s ease-in-out infinite;
  will-change: transform;
}

@keyframes float {
  0%, 100% { translate: 0 0; }
  50% { translate: 0 -1.4%; }
}

#emblem {
  display: block;
  width: max(160px, min(58vw, 50vh, 560px));
  height: auto;
  opacity: 0;
  filter: drop-shadow(0 25px 45px rgba(0, 0, 0, 0.65)) drop-shadow(0 0 40px rgba(var(--ember), 0.08));
  transition: opacity 1.4s ease;
}

#emblem.is-ready {
  opacity: 1;
}

/* ---------- Credit ---------- */

.credit {
  position: relative;
  z-index: 3;
  margin: 0;
  padding: 14px 16px max(14px, env(safe-area-inset-bottom));
  text-align: center;
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--credit-color);
  opacity: 0.7;
  pointer-events: none;
}

@media (max-width: 480px) {
  .credit {
    font-size: 10px;
    letter-spacing: 0.1em;
  }
}

@media (prefers-reduced-motion: reduce) {
  .scene::before,
  .spotlight,
  .vault-rings::before,
  .vault-rings::after,
  .emblem-wrap {
    animation: none;
  }
}