:root {
  --ink: #071a1d;
  --muted: #627477;
  --line: rgba(7, 26, 29, .14);
  --red: #ef3027;
  --cyan: #56bed2;
  --sheet-base-w: min(90vw, 1180px);
  --zoom: 1;
  --sheet-w: calc(var(--sheet-base-w) * var(--zoom));
  --sheet-h: calc(var(--sheet-w) * 1503 / 2778);
}

* { box-sizing: border-box; }
html { background: #e9ece8; }
body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background:
    radial-gradient(circle at 75% 15%, rgba(86,190,210,.16), transparent 28%),
    linear-gradient(180deg, #f8faf7 0%, #e8ece8 100%);
  font-family: Arial, Helvetica, sans-serif;
}
button, input { font: inherit; }
button { color: inherit; }
main { min-height: 100vh; padding: 22px clamp(18px, 3vw, 52px) 18px; overflow: hidden; }

.topbar {
  display: flex;
  align-items: center;
  justify-content: flex-start;
  max-width: 1320px;
  margin: 0 auto;
}
.brand-logo { display: block; width: clamp(250px, 31vw, 430px); height: auto; }

.intro { display: grid; grid-template-columns: 1.35fr .65fr; gap: 40px; max-width: 1320px; margin: clamp(32px, 6vh, 66px) auto 18px; align-items: end; }
.eyebrow { margin: 0 0 10px; color: var(--red); text-transform: uppercase; letter-spacing: .18em; font-size: 11px; font-weight: 800; }
h1 { margin: 0; font-size: clamp(36px, 5vw, 72px); line-height: .92; letter-spacing: -.055em; font-weight: 900; }
h1 span { color: transparent; -webkit-text-stroke: 1.5px var(--ink); }
.intro-copy { max-width: 470px; margin: 0 0 4px auto; font-size: 15px; line-height: 1.55; color: var(--muted); }

.viewer { max-width: 1380px; margin: 0 auto; }
.viewer-toolbar {
  position: relative;
  z-index: 20;
  display: flex;
  justify-content: flex-end;
  align-items: center;
  gap: 6px;
  max-width: 1120px;
  margin: 0 auto -4px;
}
.viewer-toolbar button {
  min-width: 42px;
  min-height: 42px;
  padding: 8px 12px;
  border: 1px solid var(--line);
  border-radius: 10px;
  color: var(--ink);
  background: rgba(255,255,255,.84);
  box-shadow: 0 5px 18px rgba(20,35,35,.07);
  font-weight: 800;
  cursor: pointer;
}
.viewer-toolbar button:hover { border-color: rgba(7,26,29,.32); transform: translateY(-1px); }
.viewer-toolbar button:disabled { opacity: .42; cursor: default; transform: none; }
.viewer-toolbar .pan-toggle { display: none; align-items: center; justify-content: center; gap: 7px; }
.viewer-toolbar .pan-toggle.active { color: white; background: var(--red); border-color: var(--red); }
.viewer-toolbar .fullscreen-toggle { display: inline-flex; align-items: center; justify-content: center; gap: 7px; min-width: 112px; background: var(--ink); color: white; }
.zoom-value { min-width: 56px; text-align: center; font-size: 12px; font-weight: 800; font-variant-numeric: tabular-nums; }
.fold-legend { display: flex; align-items: center; gap: 20px; min-height: 36px; font-size: 11px; font-weight: 700; text-transform: uppercase; letter-spacing: .08em; color: var(--muted); }
.fold-legend span { display: flex; align-items: center; gap: 7px; }
.dot { width: 9px; height: 9px; border-radius: 50%; display: inline-block; }
.dot-white { background: white; border: 1px solid #aeb8b8; }
.dot-red { background: var(--red); }
.fold-legend .status { margin-left: auto; font-variant-numeric: tabular-nums; color: var(--ink); }

.stage {
  position: relative;
  height: calc(var(--sheet-h) + 72px);
  min-height: 330px;
  perspective: 2100px;
  perspective-origin: 50% 47%;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding-top: 18px;
  cursor: ew-resize;
  touch-action: none;
  user-select: none;
}
.stage::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: linear-gradient(var(--line) 1px, transparent 1px), linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 32px 32px;
  mask-image: radial-gradient(ellipse at center, black 0%, transparent 72%);
  opacity: .24;
  pointer-events: none;
}
.flyer-canvas {
  position: absolute;
  inset: 0;
  transform: translate3d(var(--pan-x, 0px), var(--pan-y, 0px), 0);
  transform-style: preserve-3d;
  transition: transform .18s ease-out;
  pointer-events: none;
}
.stage.panning .flyer-canvas { transition: none; }
.stage.pan-mode { cursor: grab; }
.stage.panning { cursor: grabbing; }
.sheet {
  position: absolute;
  top: 18px;
  left: 50%;
  height: var(--sheet-h);
  transform-style: preserve-3d;
  transition: transform .65s cubic-bezier(.22,.8,.2,1);
  will-change: transform;
}
.stage.dragging .sheet { transition: none; }
.panel {
  position: absolute;
  top: 0;
  left: 0;
  height: var(--sheet-h);
  transform-origin: left center;
  transform-style: preserve-3d;
  transition: transform .14s linear;
  will-change: transform;
}
.stage.dragging .panel { transition: none; }
.face {
  position: absolute;
  inset: 0;
  overflow: hidden;
  backface-visibility: hidden;
  background-repeat: no-repeat;
  background-size: var(--sheet-w) var(--sheet-h);
  box-shadow: inset 0 0 0 1px rgba(0,0,0,.055), 0 0 8px rgba(4,18,20,.14);
}
.face-front { background-image: url("assets/front.jpg"); background-position: var(--front-x) 0; transform: translateZ(.45px); }
.face-back { background-image: url("assets/back.jpg"); background-position: var(--back-x) 0; transform: rotateY(180deg) translateZ(.45px); }
.panel-shade {
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: var(--shade);
  backface-visibility: hidden;
  transform: translateZ(.8px);
  background: linear-gradient(90deg, rgba(0,0,0,.28), transparent 42%, rgba(255,255,255,.12));
  mix-blend-mode: multiply;
}
.floor-shadow { position: absolute; left: 50%; bottom: 35px; width: 70%; height: 30px; border-radius: 50%; background: rgba(3,16,18,.4); filter: blur(24px); transform-origin: center; transition: .2s linear; }
.drag-hint { position: absolute; bottom: 10px; left: 50%; transform: translateX(-50%); color: var(--muted); font-size: 11px; letter-spacing: .08em; text-transform: uppercase; opacity: .75; }

.controls { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 8px; align-items: stretch; padding: 14px; border: 1px solid var(--line); background: rgba(255,255,255,.75); backdrop-filter: blur(14px); box-shadow: 0 18px 50px rgba(20,35,35,.09); border-radius: 16px; max-width: 1120px; margin: 0 auto; }
.controls button { min-height: 46px; border: 1px solid var(--line); background: white; border-radius: 10px; padding: 10px 16px; cursor: pointer; font-size: 13px; font-weight: 700; transition: .18s ease; }
.controls button:hover { transform: translateY(-1px); border-color: rgba(7,26,29,.3); }
.controls button.selected { color: white; background: var(--red); border-color: var(--red); box-shadow: 0 5px 16px rgba(239,48,39,.2); }
footer { display: flex; justify-content: space-between; gap: 30px; max-width: 1120px; margin: 14px auto 0; color: var(--muted); font-size: 11px; }
footer p { margin: 0; }

.viewer:fullscreen,
.viewer.fullscreen-fallback {
  --sheet-base-w: min(94vw, calc((100dvh - 230px) * 1.8483));
  width: 100vw;
  max-width: none;
  height: 100dvh;
  margin: 0;
  padding: max(10px, env(safe-area-inset-top)) max(10px, env(safe-area-inset-right)) max(10px, env(safe-area-inset-bottom)) max(10px, env(safe-area-inset-left));
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto;
  background:
    radial-gradient(circle at 75% 15%, rgba(86,190,210,.16), transparent 28%),
    linear-gradient(180deg, #f8faf7 0%, #e8ece8 100%);
  overflow: hidden;
}
.viewer.fullscreen-fallback { position: fixed; inset: 0; z-index: 1000; }
body.viewer-fullscreen-fallback { overflow: hidden; }
.viewer:fullscreen .viewer-toolbar,
.viewer.fullscreen-fallback .viewer-toolbar { width: min(100%, 1120px); margin-bottom: 0; }
.viewer:fullscreen .pan-toggle,
.viewer.fullscreen-fallback .pan-toggle { display: inline-flex; }
.viewer:fullscreen .stage,
.viewer.fullscreen-fallback .stage { height: auto; min-height: 0; align-self: stretch; }
.viewer:fullscreen .controls,
.viewer.fullscreen-fallback .controls { width: min(100%, 1120px); }

@media (max-width: 980px) {
  :root { --sheet-base-w: 90vw; }
  main { padding-inline: 12px; }
  .intro { grid-template-columns: 1fr; gap: 18px; margin-top: 34px; }
  .intro-copy { margin-left: 0; }
  .stage { height: calc(var(--sheet-h) + 62px); min-height: 260px; }
  .controls { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 8px; max-width: 620px; }
  footer { flex-direction: column; gap: 5px; }
}

@media (max-width: 520px) {
  .brand-logo { width: min(78vw, 340px); }
  .viewer-toolbar { justify-content: center; gap: 4px; margin-top: 8px; }
  .viewer-toolbar button { min-width: 44px; min-height: 44px; padding: 7px 10px; }
  .viewer-toolbar [data-zoom="reset"] { min-width: 44px; width: 44px; padding-inline: 0; font-size: 0; }
  .viewer-toolbar [data-zoom="reset"]::before { content: "↺"; font-size: 20px; line-height: 1; }
  .viewer-toolbar .pan-toggle { min-width: 44px; width: 44px; padding-inline: 0; font-size: 0; }
  .viewer-toolbar .pan-toggle span { font-size: 19px; }
  .viewer-toolbar .fullscreen-toggle { min-width: 104px; }
  .controls button { min-height: 48px; padding: 8px; font-size: 12px; }
  .viewer:fullscreen,
  .viewer.fullscreen-fallback {
    --sheet-base-w: min(94vw, calc((100dvh - 250px) * 1.8483));
  }
  .viewer:fullscreen .drag-hint,
  .viewer.fullscreen-fallback .drag-hint { display: none; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: .01ms !important; animation-duration: .01ms !important; }
}