:root {
  --paper: #f5ecd9;
  --paper-deep: #ead9b9;
  --ink: #1b2d2d;
  --ink-soft: #5a6c68;
  --vermilion: #b13a32;
  --vermilion-dark: #8d302d;
  --gold: #c9973d;
  --indigo: #456978;
  --sage: #78886f;
  --line: rgba(27, 45, 45, .18);
  font-family: "Noto Sans SC", "Microsoft YaHei", sans-serif;
  color: var(--ink);
  background: var(--paper);
}

* { box-sizing: border-box; }
html, body { margin: 0; min-width: 320px; min-height: 100%; background: var(--paper); }
body { overflow-x: hidden; }
button { font: inherit; }

.experience-shell { min-height: 100svh; display: grid; grid-template-columns: minmax(248px, .73fr) minmax(480px, 1.48fr) minmax(286px, .8fr); grid-template-rows: auto minmax(650px, 1fr) auto; background: var(--paper); }
.topbar { grid-column: 1 / -1; display: flex; align-items: center; justify-content: space-between; min-height: 76px; padding: 0 clamp(22px, 4vw, 64px); border-bottom: 1px solid var(--line); }
.brand-lockup { display: flex; align-items: center; gap: 12px; }
.brand-lockup strong { display: block; font-family: "Noto Serif SC", "STSong", serif; font-size: 20px; font-weight: 500; letter-spacing: .12em; }
.brand-lockup small { display: block; margin-top: 2px; color: var(--ink-soft); font-size: 10px; letter-spacing: .1em; }
.brand-seal { width: 34px; height: 34px; display: grid; place-items: center; color: var(--paper); background: var(--vermilion); font-family: "Noto Serif SC", serif; font-size: 19px; transform: rotate(-4deg); }
.topbar-meta { display: flex; gap: 26px; color: var(--ink-soft); font-size: 11px; letter-spacing: .09em; }

.intro-panel { grid-column: 1; grid-row: 2; padding: clamp(28px, 4vw, 58px) clamp(22px, 3vw, 46px); border-right: 1px solid var(--line); display: flex; flex-direction: column; }
.eyebrow { display: flex; align-items: center; gap: 9px; color: var(--vermilion); font-size: 11px; letter-spacing: .08em; }
.eyebrow-mark { width: 7px; height: 7px; background: var(--vermilion); display: inline-block; transform: rotate(45deg); }
h1 { margin: auto 0 13px; font-family: "Noto Serif SC", "STSong", serif; font-size: clamp(44px, 4.2vw, 62px); line-height: 1.08; font-weight: 500; letter-spacing: .04em; white-space: nowrap; }
.dek { max-width: 235px; margin: 0 0 42px; color: var(--ink-soft); font-family: "Noto Serif SC", serif; font-size: 18px; line-height: 1.75; }
.chapter-rail { display: grid; gap: 0; border-top: 1px solid var(--line); }
.chapter-pill { min-height: 59px; display: grid; grid-template-columns: 28px 1fr auto; gap: 8px; align-items: center; padding: 8px 0; color: var(--ink-soft); background: transparent; border: 0; border-bottom: 1px solid var(--line); text-align: left; cursor: pointer; transition: color .2s ease, padding .2s ease; }
.chapter-pill span { color: var(--gold); font-family: "Noto Serif SC", serif; font-size: 16px; }
.chapter-pill b { font-size: 14px; font-weight: 500; }
.chapter-pill small { font-size: 10px; color: var(--ink-soft); }
.chapter-pill:hover, .chapter-pill.is-active { color: var(--vermilion); padding-left: 7px; }
.chapter-pill.is-active b { font-weight: 600; }
.chapter-pill.is-active small { color: var(--vermilion); }
.intro-note { display: flex; justify-content: space-between; margin-top: auto; padding-top: 26px; color: var(--ink-soft); font-size: 10px; letter-spacing: .08em; }

.ar-stage { grid-column: 2; grid-row: 2; position: relative; min-height: 650px; overflow: hidden; background: #253f3e; isolation: isolate; }
.ar-stage::before { content: ""; position: absolute; inset: 0; z-index: -1; background: #253f3e; }
a-scene { position: absolute !important; inset: 0; width: 100%; height: 100%; }
.stage-status { position: absolute; left: 24px; top: 22px; z-index: 8; display: flex; align-items: center; gap: 8px; color: rgba(245, 236, 217, .78); font-size: 11px; }
.status-dot { width: 7px; height: 7px; background: var(--gold); border-radius: 50%; }
.stage-note { position: absolute; right: 24px; bottom: 21px; left: 24px; z-index: 8; display: flex; justify-content: space-between; color: rgba(245, 236, 217, .76); font-size: 11px; letter-spacing: .08em; }
.stage-note span:first-child { color: #e7bb65; }
.scan-ui { position: absolute; inset: 50% auto auto 50%; z-index: 7; width: min(58vw, 340px); height: min(58vw, 340px); transform: translate(-50%, -57%); pointer-events: none; display: grid; place-items: center; }
.scan-frame { position: absolute; inset: 0; border: 1px solid rgba(245, 236, 217, .28); }
.scan-frame i { position: absolute; width: 27px; height: 27px; border-color: #e7bb65; border-style: solid; }
.scan-frame i:nth-child(1) { top: -1px; left: -1px; border-width: 3px 0 0 3px; }
.scan-frame i:nth-child(2) { top: -1px; right: -1px; border-width: 3px 3px 0 0; }
.scan-frame i:nth-child(3) { bottom: -1px; left: -1px; border-width: 0 0 3px 3px; }
.scan-frame i:nth-child(4) { right: -1px; bottom: -1px; border-width: 0 3px 3px 0; }
.scan-copy { align-self: end; margin-bottom: -44px; color: rgba(245, 236, 217, .82); text-align: center; display: grid; gap: 5px; }
.scan-copy strong { font-size: 13px; font-weight: 500; }
.scan-copy span { color: rgba(245, 236, 217, .54); font-size: 11px; }

.demo-art { position: absolute; inset: 10% 14% 13%; z-index: 2; opacity: 0; pointer-events: none; transform: translateY(9px); transition: opacity .35s ease, transform .35s ease; }
.demo-art[data-chapter="0"] { --demo-accent: #d5a348; --demo-red: #b13a32; --demo-fill: rgba(27, 78, 70, .28); }
.demo-art[data-chapter="1"] { --demo-accent: #e3b451; --demo-red: #8e3b31; --demo-fill: rgba(115, 74, 45, .3); }
.demo-art[data-chapter="2"] { --demo-accent: #e5d09a; --demo-red: #2f6d72; --demo-fill: rgba(199, 151, 61, .3); }
.demo-paper { position: absolute; top: 3%; left: 50%; width: min(48%, 258px); height: 73%; transform: translateX(-50%) rotate(-1.2deg); overflow: hidden; background: #f4e6c6; box-shadow: 11px 13px 0 rgba(8, 26, 26, .24); }
.demo-paper::after { content: ""; position: absolute; inset: 10px; border: 1px solid rgba(27, 45, 45, .35); }
.demo-paper img { display: block; width: 100%; height: 100%; object-fit: cover; }
.demo-grid { position: absolute; inset: 3%; border: 1px solid rgba(231, 187, 101, .48); }
.demo-grid::before, .demo-grid::after { content: ""; position: absolute; width: 18px; height: 18px; border-color: var(--demo-accent); border-style: solid; }
.demo-grid::before { top: -1px; left: -1px; border-width: 2px 0 0 2px; }
.demo-grid::after { right: -1px; bottom: -1px; border-width: 0 2px 2px 0; }
.demo-ring { position: absolute; top: 39%; left: 50%; border: 1px solid var(--demo-accent); border-radius: 50%; transform: translate(-50%, -50%); }
.demo-ring-a { width: 22%; aspect-ratio: 1; animation: demo-spin 12s linear infinite; }
.demo-ring-b { width: 34%; aspect-ratio: 1; border-color: rgba(245, 236, 217, .44); animation: demo-spin-reverse 18s linear infinite; }
.demo-emblem { position: absolute; top: 39%; left: 50%; width: 15%; aspect-ratio: 1; display: grid; place-items: center; color: #f5e4af; background: var(--demo-red); border: 2px solid var(--demo-accent); border-radius: 50%; transform: translate(-50%, -50%); box-shadow: 0 0 0 8px var(--demo-fill); }
.demo-emblem span { font-family: "Noto Serif SC", serif; font-size: clamp(20px, 3vw, 36px); }
.demo-blade { position: absolute; top: 39%; left: 50%; width: 41%; height: 2px; background: var(--demo-accent); transform: translate(-50%, -50%) rotate(-39deg); }
.demo-caption { position: absolute; right: 4%; bottom: 2%; left: 4%; display: flex; align-items: baseline; justify-content: space-between; padding-bottom: 9px; color: #f5ecd9; border-bottom: 1px solid rgba(245, 236, 217, .38); }
.demo-caption strong { font-family: "Noto Serif SC", serif; font-size: clamp(20px, 2.4vw, 32px); font-weight: 500; }
.demo-caption span { color: var(--demo-accent); font-size: 9px; letter-spacing: .16em; }
@keyframes demo-spin { to { transform: translate(-50%, -50%) rotate(360deg); } }
@keyframes demo-spin-reverse { to { transform: translate(-50%, -50%) rotate(-360deg); } }
body.is-demo .demo-art { opacity: 1; transform: translateY(0); }
body.is-demo .scan-ui { opacity: .14; }
body.is-demo .ar-stage::after { content: "演示模式 · 可切换工艺章节"; position: absolute; top: 22px; right: 24px; z-index: 8; color: rgba(245, 236, 217, .72); font-size: 11px; }

.control-panel { grid-column: 3; grid-row: 2; min-width: 0; padding: clamp(26px, 3vw, 46px) clamp(20px, 2.8vw, 38px); background: #efe1c5; border-left: 1px solid var(--line); display: flex; flex-direction: column; align-items: stretch; }
.control-kicker { color: var(--vermilion); font-size: 10px; letter-spacing: .12em; }
.control-copy h2 { margin: 9px 0 8px; font-family: "Noto Serif SC", serif; font-size: clamp(26px, 2.6vw, 38px); font-weight: 500; line-height: 1.15; }
.control-copy p { margin: 0; color: var(--ink-soft); font-size: 13px; line-height: 1.75; }
.target-deck { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; margin: 30px 0 25px; }
.target-card { position: relative; padding: 0; border: 1px solid transparent; background: transparent; cursor: pointer; opacity: .58; transition: opacity .2s ease, transform .2s ease, border-color .2s ease; }
.target-card img { display: block; width: 100%; aspect-ratio: 3 / 4; object-fit: cover; border: 1px solid rgba(27,45,45,.16); }
.target-card span { position: absolute; left: 7px; bottom: 6px; color: #f5ecd9; font-size: 10px; }
.target-card:hover, .target-card.is-active { opacity: 1; transform: translateY(-3px); }
.target-card.is-active { border-color: var(--vermilion); }
.control-actions { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
.primary-action, .secondary-action, .icon-action { min-height: 44px; display: inline-flex; align-items: center; justify-content: center; gap: 7px; border: 1px solid var(--ink); cursor: pointer; transition: background .2s ease, color .2s ease, border-color .2s ease; }
.primary-action { color: var(--paper); background: var(--ink); }
.primary-action:hover { background: var(--vermilion); border-color: var(--vermilion); }
.secondary-action, .icon-action { color: var(--ink); background: transparent; }
.secondary-action:hover, .icon-action:hover { color: var(--vermilion); border-color: var(--vermilion); }
.icon-action { grid-column: 2; font-size: 12px; }
.action-icon { color: var(--gold); font-size: 16px; }
.control-hint { margin: auto 0 0; padding-top: 25px; color: var(--ink-soft); font-size: 11px; line-height: 1.7; border-top: 1px solid var(--line); }
.hidden { display: none !important; }
.a-enter-vr, .a-enter-ar { display: none !important; }

.site-footer { grid-column: 1 / -1; grid-row: 3; display: flex; justify-content: space-between; gap: 16px; padding: 13px clamp(22px, 4vw, 64px); color: var(--ink-soft); border-top: 1px solid var(--line); font-size: 10px; letter-spacing: .08em; }
.toast { position: fixed; right: 20px; bottom: 20px; z-index: 30; max-width: min(90vw, 380px); padding: 12px 16px; color: var(--paper); background: var(--vermilion-dark); font-size: 12px; line-height: 1.6; }

@media (max-width: 1060px) {
  .experience-shell { grid-template-columns: minmax(220px, .78fr) minmax(430px, 1.22fr); grid-template-rows: auto minmax(600px, 1fr) auto auto; }
  .intro-panel { grid-column: 1; grid-row: 2; }
  .ar-stage { grid-column: 2; grid-row: 2; }
  .control-panel { grid-column: 1 / -1; grid-row: 3; display: grid; grid-template-columns: 1fr 1.3fr 1fr; gap: 24px; align-items: center; border-top: 1px solid var(--line); border-left: 0; }
  .target-deck { margin: 0; }
  .control-hint { margin: 0; padding-top: 0; border-top: 0; }
}

@media (max-width: 680px) {
  .experience-shell { display: block; min-height: 100svh; }
  .topbar { min-height: 64px; padding: 0 18px; }
  .brand-lockup strong { font-size: 17px; }
  .topbar-meta { gap: 0; font-size: 10px; }
  .topbar-meta span:first-child { display: none; }
  .intro-panel { padding: 24px 18px 18px; border-right: 0; }
  h1 { margin: 18px 0 8px; font-size: 48px; }
  .dek { max-width: none; margin-bottom: 24px; font-size: 16px; }
  .chapter-pill { min-height: 51px; grid-template-columns: 21px 1fr; }
  .chapter-pill small { display: none; }
  .intro-note { padding-top: 18px; }
  .ar-stage { min-height: 560px; }
  .demo-art { inset: 9% 8% 13%; }
  .demo-paper { width: min(50%, 220px); height: 72%; }
  .scan-ui { width: 70vw; height: 70vw; }
  .scan-copy { margin-bottom: -36px; }
  .control-panel { display: block; padding: 24px 18px 20px; border-left: 0; border-top: 1px solid var(--line); }
  .target-deck { margin: 22px 0 18px; }
  .control-actions { grid-template-columns: 1fr 1fr; }
  .site-footer { display: block; padding: 12px 18px; line-height: 1.8; }
  .site-footer span { display: block; }
}