@font-face {
  font-family: "WeiBei Stele";
  src: url("assets/WeiBeiStele.ttf") format("truetype");
  font-display: swap;
  font-style: normal;
  font-weight: 400;
}

:root {
  color-scheme: light;
  --paper: #eee1ca;
  --paper-light: #f7eddb;
  --paper-deep: #d8c5a5;
  --ink: #25221f;
  --ink-soft: #6f675c;
  --vermilion: #b93420;
  --line: rgba(54, 47, 40, .18);
  --depth-calm: 0 34px 82px rgba(54, 40, 25, .22), 0 5px 16px rgba(54, 40, 25, .1);
  --depth-work: 0 44px 104px rgba(54, 40, 25, .24), 0 8px 22px rgba(54, 40, 25, .11);
  --depth-mini: 0 82px 190px rgba(54, 40, 25, .34), 0 18px 44px rgba(54, 40, 25, .16);
  --edge-relief: inset 0 1px 0 rgba(255,255,255,.82), inset 1px 0 0 rgba(255,255,255,.28), inset 0 -1px 0 rgba(61,49,36,.14);
  --ease-smooth-out: cubic-bezier(.22,1,.36,1);
}

* { box-sizing: border-box; }
html:not([data-scene]) { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 18% 12%, rgba(255,255,255,.5), transparent 28%),
    repeating-linear-gradient(0deg, rgba(64,49,32,.014) 0 1px, transparent 1px 4px),
    var(--paper);
  font-family: "Songti SC", "STSong", "Noto Serif CJK SC", serif;
  overflow-x: hidden;
}
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 100;
  pointer-events: none;
  opacity: .2;
  background-image:
    radial-gradient(circle, rgba(39,33,27,.16) 0 .55px, transparent .7px),
    radial-gradient(circle, rgba(255,255,255,.42) 0 .55px, transparent .7px);
  background-position: 0 0, 7px 11px;
  background-size: 15px 17px, 19px 23px;
  mix-blend-mode: multiply;
}

a { color: inherit; text-decoration: none; }
button, a { -webkit-tap-highlight-color: transparent; cursor: pointer; }
button:focus-visible, a:focus-visible { outline: 2px solid var(--vermilion); outline-offset: 5px; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }

.topbar {
  position: fixed;
  inset: 0 0 auto;
  z-index: 80;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  padding: 0 3.4vw;
  font-family: ui-sans-serif, system-ui, sans-serif;
  background: linear-gradient(to bottom, rgba(238,225,202,.94), rgba(238,225,202,.62), transparent);
}
.brand { display: inline-flex; align-items: center; gap: 10px; transform-origin: left center; transition: transform .5s var(--ease-smooth-out); will-change: transform; }
.brand img { width: 28px; height: 28px; object-fit: cover; mix-blend-mode: multiply; }
.brand span { font-family: "WeiBei Stele", serif; font-size: 17px; font-weight: 400; line-height: 1; letter-spacing: .11em; text-transform: uppercase; }
.brand i { width: 6px; height: 6px; margin: 0 0 7px -6px; align-self: flex-end; background: var(--vermilion); }
.top-actions { display: flex; align-items: center; gap: 20px; font-size: 14px; }
.github-link { display: grid; place-items: center; width: 28px; height: 28px; opacity: .72; transition: opacity .2s ease, transform .2s ease; }
.github-link svg { width: 18px; height: 18px; fill: currentColor; }
.github-link:hover { opacity: 1; transform: translateY(-1px); }
.release-nav { display: flex; align-items: center; gap: 20px; white-space: nowrap; text-align: left; }
.release-nav a { display: flex; align-items: center; height: 28px; line-height: 1; }
.release-nav a:hover, .release-nav a:focus-visible, .hero-guide:hover { color: var(--vermilion); }
.release-nav a:active, .hero-guide:active { opacity: .65; }
html[lang="zh-CN"] .release-nav a[data-en] { font-size: .93em; transform: translateY(-1px); }
.language-toggle { position: relative; display: inline-flex; align-items: center; justify-content: center; gap: 7px; width: 52px; padding: 4px 0; border: 0; color: inherit; background: transparent; font: 11px/1 ui-monospace, SFMono-Regular, Menlo, monospace; cursor: pointer; }
.language-toggle span { opacity: .38; transition: opacity .2s ease; }
.language-toggle i { width: 10px; height: 1px; background: currentColor; opacity: .28; }
html[lang="zh-CN"] .language-toggle span:first-child, html[lang="en"] .language-toggle span:last-child { opacity: 1; }
.language-toggle::after { content: ""; position: absolute; bottom: 0; left: 0; width: 11px; height: 1px; background: var(--vermilion); transition: transform .24s cubic-bezier(.16,1,.3,1); }
html[lang="en"] .language-toggle::after { transform: translateX(28px); }
.nav-download { position: relative; display: grid; place-items: center; width: auto; height: 28px; font: inherit; opacity: .78; transition: opacity .2s ease, transform .2s ease; }
.nav-download::after { content: ""; position: absolute; left: 0; right: 0; bottom: 1px; height: 1px; background: currentColor; transform: scaleX(.85); transition: transform .2s ease; }
.nav-download:hover::after { transform: scaleX(1); }
.nav-download:hover { opacity: 1; transform: translateY(-1px); }
:is(.release-nav, .nav-download, .mode-word, .theme-name, .release-title, .hero-tagline, .primary-download, .download-options) { font-family: "WeiBei Stele", serif; font-weight: 400; letter-spacing: .08em; }

.scene-rail {
  position: fixed;
  z-index: 70;
  right: 2.2vw;
  top: 50%;
  display: grid;
  gap: 9px;
  transform: translateY(-50%);
}
.scene-rail button { position: relative; display: grid; place-items: center; width: 22px; height: 22px; padding: 0; border: 0; background: transparent; cursor: pointer; }
.scene-rail button::before { content: ""; width: 5px; height: 5px; border-radius: 50%; background: rgba(65,56,47,.24); box-shadow: inset 0 0 0 1px rgba(255,255,255,.22); transition: width .3s cubic-bezier(.16,1,.3,1), height .3s cubic-bezier(.16,1,.3,1), background .3s ease, box-shadow .3s ease; }
.scene-rail button:hover::before, .scene-rail button:focus-visible::before { width: 7px; height: 7px; background: rgba(65,56,47,.52); }
.scene-rail button.is-active::before { width: 8px; height: 8px; background: var(--vermilion); box-shadow: 0 0 0 3px rgba(185,52,32,.1); }
.scene-rail button:focus-visible { outline-offset: 1px; }
.rail-label { position: absolute; right: 30px; color: var(--ink-soft); font: 12px/1.4 system-ui, sans-serif; white-space: nowrap; opacity: 0; transform: translateX(4px); pointer-events: none; transition: opacity .2s ease, transform .2s ease; }
.scene-rail button:is(:hover, :focus-visible) .rail-label { opacity: 1; transform: none; }

/* 前三幕共用应用舞台；折纸独立绘制，避免展开时连带缩放主题截图。 */
.journey-stage {
  position: fixed;
  z-index: 18;
  left: 50%;
  top: 50%;
  width: min(72vw, 1220px);
  aspect-ratio: 1.72;
  pointer-events: none;
  transform: translate3d(calc(-50% + 18vw), calc(-50% + 2vh), 0) scale(.78) rotate(0deg);
  transform-origin: center;
  will-change: transform;
}
.journey-frame { position: absolute; inset: 0; border-radius: 18px; }
.journey-layer { position: absolute; inset: 0; border-radius: 17px; opacity: 0; visibility: hidden; will-change: opacity, transform; }
.blank-layer, .experience-layer, .release-layer { border: 1px solid rgba(255,255,255,.74); }
.blank-layer { overflow: hidden; opacity: 1; background: rgba(248,239,222,.98); box-shadow: var(--depth-calm), var(--edge-relief); }
.blank-layer img { display: block; width: 100%; height: 100%; object-fit: contain; }

.experience-layer, .release-layer { overflow: hidden; background: rgba(248,239,222,.98); }
.experience-layer { box-shadow: var(--depth-work), var(--edge-relief); }
.release-layer { overflow: visible; border: 0; background: transparent; }
.window-bar { height: 8%; min-height: 38px; display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; padding: 0 15px; border-bottom: 1px solid rgba(70,58,44,.1); color: #74695c; background: rgba(255,251,242,.58); font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 9px; }
.window-bar > span:last-child { justify-self: end; }
.traffic { display: flex; gap: 6px; }
.traffic i { width: 9px; height: 9px; border-radius: 50%; background: #d66554; }
.traffic i:nth-child(2) { background: #d9ae3d; }
.traffic i:nth-child(3) { background: #4cab6b; }
.experience-page { position: absolute; inset: 8% 0 0; padding: 5% 5.5%; opacity: 0; filter: blur(2px); transform: translateY(4px) scale(.99); transition: opacity .35s ease-in-out, filter .35s ease-in-out, transform .5s var(--ease-smooth-out); }
.experience-page.is-active { opacity: 1; filter: blur(0); transform: translateY(0) scale(1); }
.experience-shot-page { z-index: 2; inset: 0; padding: 0; background: transparent; }
.experience-shot-page img { display: block; width: 100%; height: 100%; object-fit: contain; }
.experience-page h3 { margin: 0 0 3%; font-size: clamp(20px, 2vw, 32px); font-weight: 600; }
.experience-page h4 { margin: 8% 0 3%; font-size: 16px; }
.experience-page p { color: #5f574f; line-height: 1.72; }
.experience-page small, .selection-column span, .source-column span { color: var(--vermilion); font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 9px; letter-spacing: .06em; }
.experience-page[data-mode="read"]:not(.experience-shot-page) { display: grid; grid-template-columns: 1.45fr .9fr .65fr; gap: 5%; }
.selection-column, .source-column { padding-left: 9%; border-left: 1px solid var(--line); }
.selection-column blockquote { margin: 14% 0 0; padding: 13px 15px; border-left: 3px solid var(--vermilion); color: #534a40; background: rgba(184,52,32,.06); line-height: 1.65; }
.source-column p { margin: 18% 0 0; font-size: 12px; }
.text-lines { display: grid; gap: 9px; }
.text-lines i { display: block; height: 2px; background: rgba(55,47,39,.16); }
.text-lines i:nth-child(2) { width: 83%; }
.text-lines i:nth-child(3) { width: 91%; }
.text-lines i:nth-child(4) { width: 67%; }
.context-strip { width: fit-content; margin: 0 0 3% auto; padding: 7px 10px; border: 1px solid var(--line); color: #756b5e; font-size: 11px; }
.bubble { width: 62%; margin: 0 0 3% !important; padding: 13px 15px; font-size: 14px; }
.bubble.user { margin-left: auto !important; background: rgba(255,255,255,.68); }
.bubble.webi { border-left: 2px solid var(--vermilion); background: rgba(185,52,32,.05); }
.bubble small { display: block; margin-bottom: 6px; }
.answer-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1px; width: 62%; background: var(--line); }
.answer-grid span { padding: 10px; text-align: center; color: #71665a; background: rgba(255,251,242,.74); font-size: 11px; }
.input-placeholder { position: absolute; right: 5.5%; bottom: 6%; left: 5.5%; padding: 12px 14px; border: 1px solid var(--line); border-radius: 8px; color: #8e8274; font-size: 12px; }
.input-placeholder b { float: right; color: var(--ink); }
.note-row { display: flex; gap: 13px; max-width: 62%; padding: 3% 0; border-bottom: 1px solid var(--line); }
.note-row i { width: 7px; height: 7px; margin-top: 7px; flex: 0 0 auto; background: var(--vermilion); }
.note-row p { margin: 0; font-size: 14px; }
.source-link { width: fit-content; margin-top: 4%; padding: 11px 14px; color: #7e7264; background: rgba(255,255,255,.48); font-size: 12px; }
.experience-mode-label { position: absolute; z-index: 42; top: -56px; left: 0; width: 100%; height: 42px; color: rgba(46,40,34,.8); pointer-events: none; opacity: 0; transition: opacity .25s ease; }
.mode-word { position: absolute; top: 0; left: 50%; font-size: clamp(23px, 2vw, 34px); line-height: 1; letter-spacing: .08em; opacity: 0; filter: blur(2px); transform: translate(-50%, 4px) scale(.88); transition: left .5s var(--ease-smooth-out), opacity .25s ease-in-out, filter .25s ease-in-out, transform .5s var(--ease-smooth-out); }
.experience-mode-label[data-mode="overview"] .mode-word { opacity: 1; filter: blur(0); transform: translate(-50%, 0) scale(1); }
.experience-mode-label[data-mode="overview"] .mode-read { left: 18%; }
.experience-mode-label[data-mode="overview"] .mode-chat { left: 50%; }
.experience-mode-label[data-mode="overview"] .mode-write { left: 82%; }
.experience-mode-label[data-mode="read"] .mode-read,
.experience-mode-label[data-mode="chat"] .mode-chat,
.experience-mode-label[data-mode="write"] .mode-write { left: 50%; opacity: 1; filter: blur(0); transform: translate(-50%, 0) scale(1.06); }
html[data-scene="2"] .experience-mode-label { opacity: 1; }

.window-pager { position: absolute; z-index: 40; inset: 0; pointer-events: none; opacity: 0; transition: opacity .3s ease; }
.window-pager button { position: absolute; top: 50%; display: grid; place-items: center; width: 60px; height: 76px; padding: 0; border: 0; color: rgba(37,34,31,.76); background: transparent; font-size: 36px; cursor: pointer; pointer-events: none; opacity: .48; transform: translateY(-50%); transition: opacity .25s ease, transform .25s var(--ease-smooth-out); }
.window-pager button:first-child { left: -82px; }
.window-pager button:last-child { right: -82px; }
.window-pager button:hover, .window-pager button:focus-visible { opacity: 1; background: transparent; outline: 0; }
.window-pager button:active { transform: translateY(-50%) scale(.96); }
html[data-scene="2"] .window-pager { opacity: 1; }
html[data-scene="2"] .window-pager button { pointer-events: auto; }
html[data-scene="2"] .journey-stage:hover .window-pager button { opacity: .74; }
html[data-scene="2"] .window-pager button:hover, html[data-scene="2"] .window-pager button:focus-visible { opacity: 1; }
.experience-tabs { position: absolute; top: calc(100% + 18px); left: 12%; width: 76%; display: flex; justify-content: center; gap: 12px; text-align: center; font: 14px/1.8 system-ui, sans-serif; color: var(--ink-soft); visibility: hidden; opacity: 0; pointer-events: none; transition: opacity .25s ease; }
html[data-scene="2"] .experience-tabs { visibility: visible; opacity: 1; pointer-events: auto; }
.experience-tabs button { min-width: 56px; min-height: 44px; padding: 6px 10px; border: 0; border-bottom: 1px solid transparent; color: inherit; background: transparent; font: inherit; transition: color .2s ease, border-color .2s ease; }
.experience-tabs button:hover, .experience-tabs button[aria-pressed="true"] { color: var(--vermilion); border-bottom-color: currentColor; }
.experience-tabs button:active { opacity: .6; }

.themes-layer { inset: -5% -9%; overflow: hidden; padding: 6px; pointer-events: none; }
html[data-scene="3"] .themes-layer { pointer-events: auto; }
.theme-preview { position: absolute; z-index: 1; width: calc((100% - 18px) / 2); height: calc((100% - 18px) / 2); overflow: hidden; border: 0; border-radius: 11px; cursor: inherit; opacity: 1; background: #b9aa94; transition: left .62s var(--ease-smooth-out), top .62s var(--ease-smooth-out), width .62s var(--ease-smooth-out), height .62s var(--ease-smooth-out), border-radius .48s ease, opacity .3s ease, transform .62s var(--ease-smooth-out); }
.theme-preview:hover, .theme-preview:focus-visible { z-index: 5; outline: 0; }
.theme-preview::after { content: ""; position: absolute; inset: 0; z-index: 1; pointer-events: none; background: linear-gradient(180deg, rgba(20,17,15,.08), rgba(20,17,15,.24)); transition: opacity .4s ease; }
.theme-art { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; transition: opacity .42s ease, transform .68s var(--ease-smooth-out); }
.theme-paper .theme-art { object-position: center 48%; filter: sepia(.13) saturate(.72) contrast(.92) brightness(.86); }
.theme-ink .theme-art { object-position: center 64%; filter: saturate(.72) contrast(.9) brightness(.78); }
.theme-sand .theme-art { object-position: center 48%; filter: saturate(.9) contrast(.9) brightness(.9); }
.theme-blue .theme-art { object-position: center 48%; filter: saturate(.68) contrast(.92) brightness(.7); transform: scale(1.16); }
.theme-name { position: absolute; z-index: 4; left: 15px; bottom: 12px; color: rgba(250,242,227,.94); font-size: clamp(12px, .9vw, 15px); font-weight: 600; line-height: 1; letter-spacing: .08em; text-shadow: 0 1px 7px rgba(16,13,11,.78); pointer-events: none; transition: opacity .24s ease, transform .42s var(--ease-smooth-out); }
.theme-window { position: absolute; z-index: 2; left: 50%; top: 50%; display: block; width: 90%; height: 88%; overflow: hidden; transform: translate(-50%, -50%); transition: width .62s var(--ease-smooth-out), height .62s var(--ease-smooth-out); }
.theme-track { display: flex; width: 200%; height: 100%; transform: translateX(0); transition: transform .48s var(--ease-smooth-out); }
.theme-track img { display: block; width: 50%; height: 100%; flex: 0 0 50%; object-fit: contain; filter: drop-shadow(0 17px 18px rgba(18,14,11,.34)); }
.theme-preview[data-variant="dark"] .theme-track { transform: translateX(-50%); }
.theme-paper { left: 6px; top: 6px; }
.theme-ink { left: calc(50% + 3px); top: 6px; }
.theme-sand { left: 6px; top: calc(50% + 3px); }
.theme-blue { left: calc(50% + 3px); top: calc(50% + 3px); }
.themes-layer .mascot-three { z-index: 8; left: 50%; top: 50%; width: 12%; height: auto; filter: drop-shadow(0 12px 14px rgba(35,27,20,.24)); opacity: 1; transform: translate(-50%, -50%); transition: opacity .3s ease, transform .5s var(--ease-smooth-out); }

html[data-theme] .theme-preview { opacity: 0; pointer-events: none; transform: scale(.94); }
html[data-theme="paper-ink"] .theme-paper,
html[data-theme="xuan-stone"] .theme-ink,
html[data-theme="clear-glass"] .theme-sand,
html[data-theme="mist-slate"] .theme-blue { z-index: 45; left: 0; top: 0; width: 100%; height: 100%; border-color: transparent; border-radius: 17px; opacity: 1; cursor: inherit; background: transparent; box-shadow: none; pointer-events: auto; transform: scale(1); }
html[data-theme] .theme-preview .theme-art { opacity: 0; transform: scale(1.08); }
html[data-theme] .theme-preview::after { opacity: 0; }
html[data-theme] .theme-name { opacity: 0; transform: translateY(5px); }
html[data-theme] .theme-window { width: 85%; height: 92%; }
html[data-theme] .mascot-three { opacity: 0; transform: translate(-50%, -50%) scale(.82); }

.release-layer { overflow: visible; border: 0; background: transparent; }
.release-map { position: absolute; inset: -7% -10%; isolation: isolate; }
.release-destination { position: absolute; z-index: 2; display: grid; place-items: center; width: 25%; height: 27%; padding: 0 1.5% 2.4%; color: #2d2823; text-align: center; pointer-events: none; transform-origin: center; transition: transform .4s var(--ease-smooth-out), color .24s ease; }
.release-destination > img { display: block; width: 78%; height: 80%; object-fit: contain; filter: drop-shadow(0 8px 7px rgba(37,29,22,.1)); transition: transform .4s var(--ease-smooth-out), filter .4s ease; }
.release-title { position: absolute; left: 0; right: 0; bottom: 0; font-size: clamp(14px, 1.55vw, 25px); font-weight: 540; letter-spacing: .025em; transition: transform .38s var(--ease-smooth-out), opacity .22s ease; }
.release-destination:hover, .release-destination:focus-visible { z-index: 8; color: #1f1b18; transform: translateY(-7px) scale(1.025); outline: 0; }
.release-destination:hover > img, .release-destination:focus-visible > img { filter: drop-shadow(0 13px 10px rgba(37,29,22,.16)); transform: translateY(-10px); }
.release-qa { left: 12%; top: 13%; }
.release-labs { right: 12%; top: 13%; }
.release-webi { left: 11%; bottom: 16%; }
.release-feedback { right: 11%; bottom: 16%; }
html[data-scene="4"] .download-control { pointer-events: auto; }
html[data-scene="4"] .release-destination { pointer-events: auto; }

.chapter { position: relative; min-height: 170vh; }
.chapter-four { min-height: 135vh; }
.scene { position: sticky; top: 0; height: 100dvh; min-height: 720px; overflow: hidden; }
.hero-tagline { position: absolute; z-index: 10; left: 14vw; top: 56%; margin: 0; color: #5f574d; font-size: clamp(16px, 1.45vw, 23px); line-height: 1.6; white-space: nowrap; will-change: transform, opacity; }
.chapter-two .scene { background: linear-gradient(112deg, rgba(233,218,192,.9), rgba(247,237,219,.76)); }
.chapter-three .scene { isolation: isolate; background: #d8cab3; }
.theme-worlds { position: absolute; inset: 0; overflow: hidden; background: radial-gradient(circle at 50% 48%, rgba(250,241,224,.74), transparent 48%), #d8cab3; }
.theme-world { position: absolute; inset: -3%; margin: 0; overflow: hidden; opacity: 0; visibility: hidden; transition: opacity .42s ease, visibility 0s .42s; }
.theme-world::after { content: ""; position: absolute; inset: 0; background: radial-gradient(circle at 50% 49%, rgba(240,230,211,.02) 22%, rgba(25,22,20,.2) 100%), linear-gradient(to bottom, rgba(24,20,17,.12), transparent 28%, rgba(20,17,15,.08)); }
.theme-world img { display: block; width: 100%; height: 100%; object-fit: cover; filter: saturate(.86) contrast(.93) brightness(.88); }
.world-paper-ink img { object-position: center 48%; filter: sepia(.13) saturate(.72) contrast(.92) brightness(.86); }
.world-xuan-stone img { object-position: center 64%; filter: saturate(.72) contrast(.9) brightness(.78); }
.world-clear-glass img { object-position: center 48%; filter: saturate(.9) contrast(.9) brightness(.9); }
.world-mist-slate img { object-position: center 48%; filter: saturate(.68) contrast(.92) brightness(.7); transform: scale(1.25); }
.theme-world figcaption { display: none; }
.theme-world figcaption b { font-size: 15px; font-weight: 600; letter-spacing: .07em; }
.theme-world figcaption span { font-size: 12px; opacity: .72; }
html[data-scene="3"][data-theme="paper-ink"] .world-paper-ink,
html[data-scene="3"][data-theme="xuan-stone"] .world-xuan-stone,
html[data-scene="3"][data-theme="clear-glass"] .world-clear-glass,
html[data-scene="3"][data-theme="mist-slate"] .world-mist-slate { opacity: 1; visibility: visible; transition-delay: 0s; }
html[data-scene="3"][data-theme] .theme-world figcaption { opacity: 1; transform: translateY(0); }
html[data-scene="3"] .topbar { background: transparent; }
html[data-scene="3"][data-theme="xuan-stone"] .topbar,
html[data-scene="3"][data-theme="mist-slate"] .topbar,
html[data-scene="3"][data-theme="xuan-stone"] .rail-label,
html[data-scene="3"][data-theme="mist-slate"] .rail-label { color: #f3e7d4; }
html[data-scene="3"][data-theme="xuan-stone"] .compact-brand img,
html[data-scene="3"][data-theme="mist-slate"] .compact-brand img { filter: invert(.9); mix-blend-mode: normal; }
html[data-scene="3"][data-theme="xuan-stone"] .scene-rail button::before,
html[data-scene="3"][data-theme="mist-slate"] .scene-rail button::before { background: rgba(243,231,212,.34); }
html[data-scene="3"][data-theme="xuan-stone"] .scene-rail button.is-active::before,
html[data-scene="3"][data-theme="mist-slate"] .scene-rail button.is-active::before { background: var(--vermilion); }

.giant-webi { position: absolute; z-index: 2; right: -5vw; bottom: -5vh; width: min(42vw, 700px); opacity: .14; filter: brightness(.48) sepia(.3); mix-blend-mode: multiply; }
.mascot { position: absolute; z-index: 32; width: 250px; height: 250px; object-fit: contain; pointer-events: none; }
.mascot-one { left: 5vw; bottom: 1.5vh; }
.mascot-two { left: 24vw; bottom: -1vh; width: 230px; height: 230px; }

/* 背景独立合成，避免 fixed 背景附着让整页在滚动时反复重绘。 */
html[data-scene="4"], html[data-scene="4"] body { background: #eedfcb; }
body::after {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  visibility: hidden;
  background: linear-gradient(180deg, #eedfcb 0%, #ebdbc7 100%);
  transform: translateZ(0);
}
html[data-scene="4"] body::after { visibility: visible; }
.download-act { position: absolute; z-index: 6; left: 50%; bottom: -2%; width: 38%; height: 54%; pointer-events: none; transform: translateX(-50%); }
.download-act .mascot-four { position: absolute; z-index: 2; left: 50%; top: -4%; width: 88%; height: 88%; transform: translateX(-50%); }
.download-control { position: absolute; z-index: 3; left: 50%; bottom: 4%; width: 330px; color: #2e2924; filter: drop-shadow(0 9px 12px rgba(54,40,25,.18)); pointer-events: none; transform: translateX(-50%); }
.download-summary { display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 5px; height: 92px; padding: 8px 26px 16px; background: url("assets/第四幕-下载纸签-v4.webp") center / contain no-repeat; cursor: pointer; list-style: none; }
.download-summary::-webkit-details-marker { display: none; }
.download-title { font-size: 17px; font-weight: 600; letter-spacing: .045em; }
.download-summary-caption { display: flex; align-items: center; gap: 6px; color: var(--ink-soft); font-size: 10px; }
.download-summary i { font: 14px/1 Georgia, serif; transition: transform .25s ease; }
.download-control[open] .download-summary i { transform: rotate(180deg); }
.download-summary:focus-visible, .download-paper :is(button, a):focus-visible { outline: 2px solid var(--vermilion); outline-offset: 3px; }
.download-control[open] { width: min(580px, 76vw); bottom: -10%; padding: 8px 26px 22px; }
.download-control[open]::before { content: ""; position: absolute; inset: 0; pointer-events: none; background: repeating-linear-gradient(17deg, #796a5005 0 .4px, transparent .8px 5px), repeating-linear-gradient(97deg, #fff9ed33 0 .4px, transparent .8px 3px), var(--paper-light); box-shadow: inset 0 0 12px #b9a48044; clip-path: polygon(1% 1.5%, 15% .4%, 38% 1%, 62% .2%, 83% 1%, 99% .5%, 99.5% 26%, 99% 52%, 100% 76%, 99% 98%, 78% 99%, 54% 98.5%, 31% 100%, 1% 98%, .4% 72%, 1% 48%, 0 23%); }
.download-control[open] .download-summary { position: relative; height: auto; min-height: 44px; padding: 5px 20px 10px; background: none; }
.download-control[open] .download-summary-caption { position: absolute; right: 0; top: 12px; }
.download-control[open] .download-summary-caption > span { display: none; }
.download-paper { position: relative; display: grid; gap: 16px; animation: download-unfold .32s var(--ease-smooth-out); }
.download-options { display: flex; justify-content: center; gap: 28px; border-bottom: 1px solid var(--line); }
.download-options button { padding: 8px 16px 10px; border: 0; border-bottom: 2px solid transparent; color: var(--ink-soft); background: none; font: inherit; font-size: 13px; cursor: pointer; }
.download-options button[aria-pressed="true"] { border-bottom-color: var(--vermilion); color: var(--vermilion); }
.primary-download { display: flex; align-items: center; justify-content: center; justify-self: center; flex-wrap: wrap; gap: 10px; min-height: 44px; padding: 10px 24px; border-radius: 4px; color: var(--paper-light); background: var(--vermilion); font-size: 15px; letter-spacing: .025em; }
.primary-download:hover { background: #a32e1d; }
.download-chip { padding-left: 12px; border-left: 1px solid #f7eddb55; font-size: 11px; }
.download-homebrew { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 12px 14px; border: 1px solid var(--line); border-radius: 3px; font-size: 12px; }
.download-homebrew > span:last-child { color: var(--ink-soft); font-size: 11px; }
.release-map, .download-act .mascot-four { transition: transform .4s var(--ease-smooth-out); }
.release-layer:has(.download-control[open]) .release-map { transform: translateY(-8%) scale(.9); }
.release-layer:has(.download-control[open]) .mascot-four { transform: translate(-50%, -44%) scale(.74); }
.release-layer:has(.download-control[open]) .release-webi { left: 1%; }
.release-layer:has(.download-control[open]) .release-feedback { right: 1%; }
@keyframes download-unfold { from { opacity: 0; transform: translateY(-8px); } to { opacity: 1; transform: translateY(0); } }

@supports (animation-timeline: scroll()) {
  .hero-tagline { animation: hero-tagline-journey 1s linear both; animation-timeline: scroll(root block); }
  .compact-brand { animation: brand-journey 1s linear both; animation-timeline: scroll(root block); }
  .journey-stage { animation: stage-journey 1s linear both; animation-timeline: scroll(root block); }
  .blank-layer { animation: blank-journey 1s linear both, blank-visibility 1s linear both; animation-timeline: scroll(root block); }
  .experience-layer { animation: experience-journey 1s linear both, experience-visibility 1s linear both; animation-timeline: scroll(root block); }
  .themes-layer { animation: themes-journey 1s linear both, themes-visibility 1s linear both; animation-timeline: scroll(root block); }
  .release-layer { animation: release-journey 1s linear both, release-visibility 1s linear both; animation-timeline: scroll(root block); }
  .release-destination { animation: map-destination-journey 1s linear both; animation-timeline: scroll(root block); }

  @keyframes hero-tagline-journey {
    0%, 12% { opacity: 1; transform: translateY(0); }
    19%, 100% { opacity: 0; transform: translateY(-12px); }
  }
  @keyframes brand-journey {
    0%, 12% { transform: translate3d(2.6vw, calc(46vh - 36px), 0) scale(3.2); animation-timing-function: var(--ease-smooth-out); }
    17% { transform: translate3d(1.45vw, calc(24vh - 20px), 0) scale(2.05); animation-timing-function: var(--ease-smooth-out); }
    23%, 100% { transform: translate3d(0, 0, 0) scale(1); }
  }

  @keyframes stage-journey {
    0%, 18% { transform: translate3d(calc(-50% + 18vw), calc(-50% + 2vh), 0) scale(.78) rotate(0deg); }
    28%, 49% { transform: translate3d(-50%, -50%, 0) scale(.88) rotate(0deg); }
    58% { transform: translate3d(-50%, -50%, 0) scale(.94) rotate(0deg); }
    63%, 100% { transform: translate3d(-50%, -50%, 0) scale(.98) rotate(0deg); }
  }
  @keyframes blank-journey { 0%, 20% { opacity: 1; transform: scale(1); } 28%, 100% { opacity: 0; transform: scale(1.025); } }
  @keyframes experience-journey { 0%, 20% { opacity: 0; transform: scale(.985); } 28%, 49% { opacity: 1; transform: scale(1); } 57%, 100% { opacity: 0; transform: scale(.98); } }
  @keyframes themes-journey { 0%, 50% { opacity: 0; transform: scale(.9); } 58% { opacity: 1; transform: scale(.97); } 63%, 78% { opacity: 1; transform: scale(1); } 85%, 100% { opacity: 0; transform: scale(1); } }
  @keyframes release-journey { 0%, 79% { opacity: 0; } 84%, 100% { opacity: 1; } }
  /* 可见性单独管理，避免把变形与透明度动画拖回主线程。 */
  @keyframes blank-visibility { 0%, 20% { visibility: visible; } 28%, 100% { visibility: hidden; } }
  @keyframes experience-visibility { 0%, 20% { visibility: hidden; } 28%, 49% { visibility: visible; } 57%, 100% { visibility: hidden; } }
  @keyframes themes-visibility { 0%, 50% { visibility: hidden; } 58%, 78% { visibility: visible; } 85%, 100% { visibility: hidden; } }
  @keyframes release-visibility { 0%, 79% { visibility: hidden; } 84%, 100% { visibility: visible; } }
  @keyframes map-destination-journey {
    0%, 85% { opacity: 0; transform: translateY(22px) scale(.82); }
    91%, 100% { opacity: 1; transform: translateY(0) scale(1); }
  }
}

@supports not (animation-timeline: scroll()) {
  .journey-stage { transition: transform .8s cubic-bezier(.16,1,.3,1); }
  html[data-scene="1"] .compact-brand { transform: translate3d(2.6vw, calc(46vh - 36px), 0) scale(3.2); }
  html:not([data-scene="1"]) .hero-tagline { opacity: 0; transform: translateY(-12px); }
  html[data-scene="2"] .journey-stage { transform: translate3d(-50%, calc(-50% - 1vh), 0) scale(.88) rotate(.5deg); }
  html[data-scene="3"] .journey-stage { transform: translate3d(-50%, -50%, 0) scale(.98) rotate(0deg); }
  html[data-scene="4"] .journey-stage { transform: translate3d(-50%, -50%, 0) scale(.98); }
  html[data-scene="1"] .blank-layer, html[data-scene="2"] .experience-layer, html[data-scene="3"] .themes-layer, html[data-scene="4"] .release-layer { opacity: 1; visibility: visible; }
  .release-destination { opacity: 0; transform: translateY(22px) scale(.82); }
  html[data-scene="4"] .release-destination { animation: map-destination-open .46s var(--ease-smooth-out) .5s both; }
  @keyframes map-destination-open { to { opacity: 1; transform: translateY(0) scale(1); } }
}

@media (max-width: 1050px) {
  .scene { min-height: 620px; }
  .journey-stage { width: 78vw; }
  .copy-two, .copy-three { width: 35vw; }
  .scene-rail { display: none; }
}

@media (max-width: 760px) {
  html { scroll-snap-type: y mandatory; }
  body { overscroll-behavior-y: contain; }
  body::before { display: none; }
  .topbar { height: 58px; padding: 0 5vw; background: linear-gradient(to bottom, rgba(238,225,202,.98), rgba(238,225,202,.78), transparent); }
  .brand { gap: 7px; transform: none !important; animation: none !important; }
  .brand img { width: 23px; height: 23px; }
  .brand span { font-size: 14px; }
  .top-actions { gap: 13px; font-size: 12px; }
  .nav-download, .language-toggle { min-width: 44px; min-height: 44px; }
  .top-actions > a:first-child { display: none; }
  .release-nav { position: fixed; top: 58px; left: 0; right: 0; justify-content: center; height: 44px; gap: 16px; font-size: 11px; background: linear-gradient(to bottom, rgba(238,225,202,.9), transparent); }
  .release-nav a { min-width: 44px; height: 44px; justify-content: center; }
  html[data-scene="3"] .release-nav { background: transparent; }
  .language-toggle { font-size: 9px; }
  .scene { min-height: 100dvh; }
  .chapter, .chapter-four { min-height: 100dvh; scroll-snap-align: start; scroll-snap-stop: always; }
  .hero-tagline { left: 7vw; top: 22%; width: 86vw; font-size: 18px; text-align: center; white-space: normal; }
  .giant-webi { display: none; }
  .mascot-one { left: 4vw; bottom: 8vh; width: 132px; height: 132px; }
  .mascot-two { left: 2vw; bottom: 4vh; width: 128px; height: 128px; }

  .journey-stage { top: 52%; width: 92vw; animation: none !important; transform: translate3d(-50%, -50%, 0) !important; }
  .journey-layer {
    visibility: hidden;
    opacity: 0 !important;
    transform: translate3d(0, 8px, 0) scale(.99) !important;
    animation: none !important;
    transition: opacity .25s ease-in-out, transform .25s var(--ease-smooth-out), visibility 0s linear .25s;
    will-change: auto;
  }
  html[data-scene="1"] .blank-layer,
  html[data-scene="2"] .experience-layer,
  html[data-scene="3"] .themes-layer,
  html[data-scene="4"] .release-layer {
    visibility: visible;
    opacity: 1 !important;
    transform: translate3d(0, 0, 0) scale(1) !important;
    transition-delay: 0s;
  }
  html[data-scene="1"] .journey-stage { top: 54%; transform: translate3d(-50%, -50%, 0) !important; }
  html[data-scene="2"] .journey-stage { top: 48%; transform: translate3d(-50%, -50%, 0) !important; }
  .experience-mode-label { top: -38px; }
  .mode-word { font-size: 17px; }
  .window-pager { display: none; }
  .experience-tabs { top: calc(100% + 20px); left: 0; width: 100%; gap: 8px; font-size: 13px; }
  .experience-tabs button { min-width: 60px; }

  html[data-scene="3"] .journey-stage { top: 52%; width: 100vw; height: 72dvh; aspect-ratio: auto; transform: translate3d(-50%, -50%, 0) !important; }
  .themes-layer { inset: 0; padding: 3px; }
  .theme-preview { width: calc((100% - 9px) / 2); height: calc((100% - 9px) / 2); border-radius: 8px; touch-action: pan-y; }
  .theme-paper { left: 3px; top: 3px; }
  .theme-ink { left: calc(50% + 1.5px); top: 3px; }
  .theme-sand { left: 3px; top: calc(50% + 1.5px); }
  .theme-blue { left: calc(50% + 1.5px); top: calc(50% + 1.5px); }
  .theme-window { width: 94%; height: 84%; }
  .theme-name { left: 10px; bottom: 9px; font-size: 11px; }
  .themes-layer .mascot-three { width: 24%; }
  html[data-theme] .theme-preview { transition: opacity .15s ease-in-out, transform .35s var(--ease-smooth-out), border-radius .25s ease; }
  html[data-theme="paper-ink"] .theme-paper,
  html[data-theme="xuan-stone"] .theme-ink,
  html[data-theme="clear-glass"] .theme-sand,
  html[data-theme="mist-slate"] .theme-blue { width: calc((100% - 9px) / 2); height: calc((100% - 9px) / 2); transform: scale(2.02); }
  html[data-theme="paper-ink"] .theme-paper { left: 3px; top: 3px; transform-origin: top left; }
  html[data-theme="xuan-stone"] .theme-ink { left: calc(50% + 1.5px); top: 3px; transform-origin: top right; }
  html[data-theme="clear-glass"] .theme-sand { left: 3px; top: calc(50% + 1.5px); transform-origin: bottom left; }
  html[data-theme="mist-slate"] .theme-blue { left: calc(50% + 1.5px); top: calc(50% + 1.5px); transform-origin: bottom right; }
  html[data-scene="3"][data-theme] .theme-window { width: 94%; height: 78%; }

  .release-layer { overflow: hidden; }
  .release-map { inset: 0; }
  .release-destination { width: 42%; height: 22%; padding: 0 2% 5%; animation: none !important; opacity: 1 !important; transform: none !important; }
  .release-destination > img { width: 70%; height: 74%; }
  .release-title { font-size: 15px; }
  .release-qa { left: 5%; top: 6%; }
  .release-labs { right: 5%; top: 6%; }
  .release-webi { left: 5%; bottom: 20%; }
  .release-feedback { right: 5%; bottom: 27%; }
  .download-act { bottom: 7%; width: 52%; height: 31%; }
  .download-act .mascot-four { top: -17%; width: 110%; height: 110%; }
  .download-control { bottom: 0; width: min(300px, 86vw); }
  .download-summary { height: 86px; }
  .download-title { font-size: 15px; }
  .download-control[open] { bottom: -8%; width: 92vw; padding: 6px 16px 18px; }
  .download-paper { gap: 12px; }
  .download-options { gap: 16px; }
  .download-options button { min-height: 44px; }
  .download-homebrew { flex-wrap: wrap; gap: 5px; }
  .release-layer:has(.download-control[open]) .release-webi { left: 3%; bottom: 43%; }
  .release-layer:has(.download-control[open]) .release-feedback { right: 3%; bottom: 43%; }
  .release-layer:has(.download-control[open]) .release-map { transform: translateY(-3%) scale(.94); }
  .release-layer:has(.download-control[open]) .mascot-four { transform: translate(-50%, -58%) scale(.65); }

}

@media (max-width: 760px) and (max-height: 680px) and (orientation: portrait) {
  .release-layer:has(.download-control[open]) .release-webi,
  .release-layer:has(.download-control[open]) .release-feedback { bottom: 53%; }
  .release-layer:has(.download-control[open]) .mascot-four { transform: translate(-50%, -100%) scale(.65); }
  .hero-tagline { top: 20%; }
  html[data-scene="1"] .journey-stage { top: 64%; }
  .mascot-one { width: 100px; height: 100px; bottom: 1vh; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .001ms !important; animation-iteration-count: 1 !important; transition-duration: .001ms !important; }
  .journey-stage { animation: none !important; }
  html[data-scene="1"] .compact-brand { transform: translate3d(2.6vw, calc(46vh - 36px), 0) scale(3.2); }
  html[data-scene="2"] .journey-stage { transform: translate3d(-50%, calc(-50% - 1vh), 0) scale(.88) rotate(.5deg); }
  html[data-scene="3"] .journey-stage { transform: translate3d(-50%, -50%, 0) scale(.98) rotate(0deg); }
  html[data-scene="4"] .journey-stage { transform: translate3d(-50%, -50%, 0) scale(.98); }
  .journey-layer { opacity: 0 !important; }
  html[data-scene="1"] .blank-layer, html[data-scene="2"] .experience-layer, html[data-scene="3"] .themes-layer, html[data-scene="4"] .release-layer { opacity: 1 !important; visibility: visible; }
  .release-destination { clip-path: none !important; opacity: 1 !important; transform: none !important; }
}


/* Keep product information in the existing first-scene copy area. */
.hero-tagline h1 { margin: 0; font: inherit; letter-spacing: inherit; }
.hero-description { max-width: min(29em, 26vw); margin: 12px 0 10px; font: 14px/1.9 system-ui, sans-serif; letter-spacing: .02em; white-space: normal; }
.hero-guide { font: 13px/1.8 system-ui, sans-serif; letter-spacing: .02em; text-decoration: underline; text-underline-offset: 4px; }
html[lang="en"] .hero-tagline { max-width: 26vw; white-space: normal; }
@media (max-width: 760px) {
  html[lang="en"] .hero-tagline { max-width: none; }
  .hero-description { max-width: 25em; margin: 10px auto 8px; font-size: 13px; }
}