:root {
  color-scheme: dark;
  --bg: #05070a;
  --bg-soft: #0e141b;
  --lamp: rgba(241, 204, 132, 0.24);
  --paper: #d9d0bf;
  --paper-ink: #1f1b16;
  --envelope: #c8b298;
  --envelope-edge: #ad9476;
  --gold: #d4b053;
  --gold-edge: #9a7a2a;
  --accent: #80c8ff;
  --touch: 44px;
  --card-w: clamp(320px, 90vw, 720px);
  --note-w: min(100%, calc(var(--card-w) - clamp(2rem, 5vw, 4rem)));
}
* { box-sizing: border-box; }
body {
  margin: 0;
  min-height: 100vh;
  font-family: "Courier New", Courier, monospace;
  background:
    radial-gradient(130vmax 90vmax at 20% -8%, var(--lamp), transparent 60%),
    radial-gradient(120vmax 80vmax at 50% 55%, #111927 0%, transparent 58%),
    radial-gradient(circle at 50% 45%, transparent 55%, rgba(0, 0, 0, 0.65) 100%),
    var(--bg);
  color: #f2ece0;
  overflow-x: hidden;
}
body::after {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: 0.12;
  background-image: radial-gradient(rgba(255,255,255,0.2) 0.4px, transparent 0.4px);
  background-size: 3px 3px;
}
.scene {
  max-width: 1080px;
  margin: 0 auto;
  padding: clamp(1rem, 3vw, 2rem);
}
.scene-header { text-align: center; margin-bottom: 1rem; }
.scene-header h1 { margin: 0; font-size: clamp(1.4rem, 2.8vw, 2rem); }
.scene-header p { margin: 0.4rem 0 0; opacity: 0.8; }
.envelope-stage { display: grid; grid-template-columns: auto 1fr auto; gap: .8rem; align-items: center; }
.nav-arrow {
  min-width: var(--touch); min-height: var(--touch); border-radius: 999px;
  border: 1px solid rgba(255,255,255,0.35); background: rgba(16,24,36,.75); color: #f9f5ea;
  font-size: 1.1rem; cursor: pointer;
}
.envelope {
  position: relative;
  width: var(--card-w);
  max-width: 100%;
  justify-self: center;
  min-height: 66vh;
  padding: clamp(1rem, 2.5vw, 2rem);
  border-radius: 22px;
  transform-style: preserve-3d;
  perspective: 900px;
  background: linear-gradient(160deg, rgba(28,36,48,.65), rgba(10,12,18,.85));
  box-shadow: 0 25px 45px rgba(0,0,0,.5), inset 0 1px 0 rgba(255,255,255,.08);
  outline: none;
  cursor: pointer;
  transition: box-shadow .25s ease;
}
.envelope:focus-visible {
  box-shadow: 0 25px 45px rgba(0,0,0,.5), inset 0 1px 0 rgba(255,255,255,.08), 0 0 0 3px rgba(128, 200, 255, .45);
}
.envelope::before {
  content: none;
}
.envelope.finale { cursor: default; }

.envelope-internals {
  position: absolute;
  inset: 14% 20%;
  border-radius: 18px;
  transform-style: preserve-3d;
  pointer-events: none;
}

.flap {
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  height: 36%;
  z-index: 5;
  background: linear-gradient(180deg, rgba(255,255,255,.25), rgba(0,0,0,.1)), var(--envelope-edge);
  clip-path: polygon(0 0, 100% 0, 50% 100%);
  transform-origin: top center;
  transform: rotateX(0deg) translateZ(4px);
  transition: transform .62s cubic-bezier(.22, .61, .23, 1);
}

.pocket-back,
.front-face {
  position: absolute;
  inset: 0;
  border-radius: 18px;
}

.pocket-back {
  z-index: 1;
  background: linear-gradient(160deg, var(--envelope), var(--envelope-edge));
  box-shadow: inset 0 2px 4px rgba(255,255,255,.28), 0 12px 15px rgba(0,0,0,.35);
  transform: translateZ(-2px);
}

.content-origin {
  position: absolute;
  left: clamp(1rem, 3vw, 1.8rem);
  right: clamp(1rem, 3vw, 1.8rem);
  top: clamp(1rem, 3vw, 1.8rem);
  bottom: clamp(1rem, 3vw, 1.8rem);
  z-index: 2;
  transform-style: preserve-3d;
}

.front-face {
  z-index: 4;
  clip-path: polygon(0 38%, 50% 74%, 100% 38%, 100% 100%, 0 100%);
  background: linear-gradient(168deg, #c9b69f, #ab9275);
  box-shadow: inset 0 2px 2px rgba(255,255,255,.18);
  transform: translateZ(6px);
}

.envelope.finale .pocket-back,
.envelope.finale .front-face {
  background: linear-gradient(160deg, var(--gold), var(--gold-edge));
}

/* CLOSED / OPENING / OPEN level states. */
.envelope[data-state="closed"] {
  transform: translateY(0) rotateX(0) rotateZ(0);
}
.envelope[data-state="opening"] {
  animation: envelope-pickup .58s cubic-bezier(.2, .7, .2, 1) both;
}
.envelope[data-state="closed"] .flap { transform: rotateX(0deg); }
.envelope[data-state="opening"] .flap,
.envelope[data-state="open"] .flap { transform: rotateX(-158deg) translateZ(12px); }

.seal {
  position: absolute; top: 30%; left: 50%; transform: translate(-50%, -50%);
  width: 74px; height: 74px; border-radius: 50%; z-index: 4;
  display: grid; place-items: center; text-align: center; padding-top: .3rem;
  background: radial-gradient(circle at 35% 28%, rgba(255,255,255,.4), rgba(100,35,20,.9));
  box-shadow: inset 0 2px 3px rgba(255,255,255,.25), 0 8px 18px rgba(0,0,0,.45);
}
.seal span { font-size: 1.5rem; font-weight: 700; }
.seal small { font-size: .58rem; letter-spacing: .08em; }

.open-hint {
  position: absolute;
  top: calc(30% + 52px);
  left: 50%;
  z-index: 5;
  transform: translateX(-50%);
  margin: 0;
  font-size: .82rem;
  opacity: .82;
  transition: opacity .35s ease;
}
.envelope[data-state="opening"] .open-hint,
.envelope[data-state="open"] .open-hint,
.envelope[data-hint-seen="true"] .open-hint {
  opacity: 0;
}

.artifacts {
  position: relative;
  z-index: 2;
  margin-top: clamp(4.2rem, 8.5vw, 5.2rem);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  align-items: start;
  visibility: hidden;
  transform-style: preserve-3d;
}
.note, .photo, .finale {
  padding: 1rem;
  border-radius: 12px;
  box-shadow: 0 10px 22px rgba(0,0,0,.32);
}
.note {
  width: var(--note-w);
  max-width: 100%;
  color: var(--paper-ink);
  background: linear-gradient(170deg, #e9e1d0, #cec1ac);
  min-height: 220px;
  white-space: normal;
  overflow-wrap: anywhere;
  overflow: hidden;
  transform: rotate(-1.4deg);
}
.photo {
  width: var(--note-w);
  max-width: 100%;
  background: #f5f5f5;
  transform: rotate(1.4deg);
  margin: 0;
}
.photo img, #finale-image { width: 100%; height: auto; display: block; border-radius: 8px; }
.typewriter-buffer {
  width: 100%;
  max-width: 100%;
  min-height: 9.2rem;
  line-height: 1.55;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

/* Artifacts emerge after flap opens, note first then photo. */
.note,
.photo {
  opacity: 0;
  transform-origin: center top;
  transition-property: opacity, transform;
  transition-duration: .52s;
  transition-timing-function: cubic-bezier(.17, .82, .28, 1.08);
}
.note {
  transform: translateY(42px) translateZ(1px) rotate(-2.3deg) scale(.96);
  transition-delay: .24s;
}
.photo {
  transform: translateY(56px) translateZ(1px) rotate(2.2deg) scale(.95);
  transition-delay: .34s;
}

.envelope[data-state="opening"] .artifacts,
.envelope[data-state="open"] .artifacts {
  visibility: visible;
}
.envelope[data-state="opening"] .note,
.envelope[data-state="open"] .note {
  opacity: 1;
  transform: translateY(8px) translateZ(2px) rotate(-1.4deg) scale(1.01);
}
.envelope[data-state="opening"] .photo,
.envelope[data-state="open"] .photo {
  opacity: 1;
  transform: translateY(14px) translateZ(2px) rotate(1.4deg) scale(1);
}

.envelope[data-state="open"] .note,
.envelope[data-state="open"] .photo {
  transform: translateY(-4px) translateZ(15px) rotate(-1.4deg) scale(1.01);
}

.envelope[data-state="open"] .photo {
  transform: translateY(2px) translateZ(13px) rotate(1.4deg) scale(1);
}

.answer-zone {
  position: relative;
  z-index: 3;
  margin-top: 1rem;
  max-width: 520px;
  display: grid;
  gap: .45rem;
}
.answer-zone label { font-size: .9rem; opacity: .8; }
.answer-zone input {
  min-height: var(--touch); font-size: 1rem; padding: .75rem .9rem;
  border: 1px solid rgba(255,255,255,.35); border-radius: 10px;
  background: rgba(7,10,16,.8); color: #f8f4eb;
}
.envelope[data-state="closed"] .answer-zone,
.envelope[data-state="opening"] .answer-zone {
  visibility: hidden;
  pointer-events: none;
}
.answer-zone.shake input { animation: shake .15s linear 2; }
@keyframes shake { 0%,100%{transform:translateX(0)} 25%{transform:translateX(3px)} 75%{transform:translateX(-3px)} }

.finale {
  position: relative; z-index: 3; margin-top: clamp(9rem, 14vw, 10.5rem); color: #fff6de;
  background: linear-gradient(150deg, rgba(197,150,43,.33), rgba(49,34,7,.68));
}
.scene-footer { margin-top: .8rem; text-align: center; }
#reset-progress {
  min-height: var(--touch); padding: .5rem 1rem; border-radius: 999px; border: 1px solid rgba(255,255,255,.4);
  background: rgba(10,12,20,.65); color: #e9e4d9;
}

@keyframes envelope-pickup {
  0% { transform: translateY(0) rotateX(0deg) rotateZ(0deg); }
  45% {
    transform: translateY(-8px) rotateX(4deg) rotateZ(-.8deg);
    box-shadow: 0 16px 28px rgba(0,0,0,.44), inset 0 1px 0 rgba(255,255,255,.08);
  }
  100% {
    transform: translateY(0) rotateX(0deg) rotateZ(0deg);
    box-shadow: 0 25px 45px rgba(0,0,0,.5), inset 0 1px 0 rgba(255,255,255,.08);
  }
}

@media (max-width: 780px) {
  .envelope-stage { grid-template-columns: 1fr; }
  .nav-arrow { justify-self: center; }
  .artifacts { grid-template-columns: 1fr; margin-top: 8.8rem; }
  .note, .photo { transform: none; }
  .answer-zone input { font-size: 16px; }
}