:root {
  --bg: #fafafa; --surface: #fff; --soft: #f1f1f3; --line: #dedee3;
  --text: #18181b; --muted: #707078; --inverse: #fff;
  --shadow: 0 28px 80px #18181b0d;
  font-family: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans CJK SC", "Microsoft YaHei", sans-serif;
  color-scheme: light; font-synthesis: none; text-rendering: optimizeLegibility;
}
:root[data-theme="dark"] {
  --bg: #0c0c0d; --surface: #171719; --soft: #222225; --line: #343439;
  --text: #f4f4f5; --muted: #aaaab2; --inverse: #18181b; --shadow: 0 28px 80px #0005;
  color-scheme: dark;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 110px; }
body { margin: 0; background: var(--bg); color: var(--text); line-height: 1.7; }
[hidden] { display: none !important; }
.symbol-definitions { position: absolute; width: 0; height: 0; overflow: hidden; }
a { color: inherit; text-decoration: none; }
button { font: inherit; cursor: pointer; }
button, a { -webkit-tap-highlight-color: transparent; }
a:focus-visible, button:focus-visible, summary:focus-visible { outline: 2px solid var(--text); outline-offset: 5px; }
svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 1.65; stroke-linecap: round; stroke-linejoin: round; flex-shrink: 0; }
h1, h2, h3, p, figure { margin: 0; }
h1, h2, h3 { font-weight: 620; letter-spacing: -.05em; }
.section-width { width: min(1200px, calc(100% - 96px)); margin-inline: auto; }
.skip-link { position: fixed; top: -80px; left: 20px; z-index: 10; background: var(--text); color: var(--inverse); padding: 10px 18px; border-radius: 8px; }
.skip-link:focus { top: 16px; }
.site-header { height: 92px; width: min(1440px, 100%); margin: auto; padding: 0 48px; display: flex; align-items: center; gap: 40px; position: relative; z-index: 5; }
.brand { display: inline-flex; align-items: center; gap: 12px; white-space: nowrap; }
.brand > span { font-size: 21px; letter-spacing: .02em; font-weight: 700; line-height: 1.2; }
.brand small { display: block; font-size: 9px; font-weight: 500; letter-spacing: 2px; color: var(--muted); margin-top: 6px; }
:root[data-theme="dark"] .brand img { filter: invert(1); }
.header-nav { display: flex; gap: 26px; margin-inline: auto; font-size: 12px; color: var(--muted); }
.header-nav a:hover, .site-footer a:hover { color: var(--text); }
.header-actions { display: flex; align-items: center; gap: 20px; }
.login-link { font-size: 13px; min-height: 40px; display: inline-flex; align-items: center; }
.theme-toggle { width: 38px; height: 40px; padding: 0; display: grid; place-items: center; border: 0; border-radius: 9px; background: transparent; color: var(--muted); }
.theme-toggle:hover { background: var(--soft); color: var(--text); }
.theme-toggle svg { width: 19px; height: 19px; }
.button { display: inline-flex; justify-content: center; align-items: center; gap: 30px; padding: 15px 23px; min-height: 52px; border: 1px solid var(--text); border-radius: 10px; background: var(--text); color: var(--inverse); font-size: 14px; font-weight: 550; transition: transform .18s, opacity .18s; }
.button:hover { opacity: .86; transform: translateY(-2px); }
.button.small { padding: 9px 15px; min-height: 40px; gap: 12px; font-size: 12px; border-radius: 8px; }
.button.small svg { width: 16px; height: 16px; }
.text-link { display: inline-flex; align-items: center; gap: 13px; font-size: 13px; }
.text-link svg { width: 17px; }
.menu-button { display: none; width: 36px; height: 40px; padding: 0; border: 0; background: transparent; color: var(--text); align-items: center; justify-content: center; }
.mobile-menu { position: absolute; inset: 80px 16px auto; background: var(--surface); padding: 20px; border: 1px solid var(--line); border-radius: 16px; box-shadow: var(--shadow); }
.mobile-menu > a { display: block; padding: 10px 0; }
.eyebrow { color: var(--muted); font-size: 10px; font-weight: 550; letter-spacing: 2px; }
.status-dot, .note-dot { display: inline-block; width: 5px; height: 5px; border-radius: 50%; background: currentColor; vertical-align: middle; margin-right: 8px; }
.hero { min-height: 670px; padding: 92px 0 100px; display: grid; grid-template-columns: .95fr 1.2fr; gap: 70px; align-items: center; }
.hero h1 { font-size: clamp(42px, 4.5vw, 66px); line-height: 1.25; margin-top: 30px; letter-spacing: -.055em; }
.serif-word { font-family: "Noto Serif CJK SC", "Songti SC", "STSong", serif; font-weight: 500; }
.hero-description { color: var(--muted); font-size: 15px; line-height: 2; margin-top: 25px; }
.hero-actions { display: flex; gap: 24px; align-items: center; flex-wrap: wrap; margin-top: 32px; }
.hero-note { margin-top: 24px; display: flex; align-items: center; gap: 8px; font-size: 10px; color: var(--muted); }
.hero-note svg { width: 14px; height: 14px; }
.hero-note > span { margin: 0 2px; }
.hero-scene { position: relative; padding: 20px 0 55px; }
.scene-glow { position: absolute; inset: -90px 0 -30px; background: radial-gradient(ellipse, var(--soft), transparent 68%); pointer-events: none; }
.room-preview { position: relative; border: 1px solid var(--line); border-radius: 17px; background: var(--surface); padding: 0 13px; box-shadow: 0 30px 90px #18181b15, 0 4px 12px #18181b06; transform: perspective(1400px) rotateY(-5deg) rotateX(2deg); }
:root[data-theme="dark"] .room-preview { box-shadow: 0 30px 90px #0008; }
.preview-top { height: 49px; display: flex; align-items: center; gap: 15px; font-size: 10px; color: var(--muted); }
.window-dots { display: flex; gap: 4px; }
.window-dots i { width: 5px; height: 5px; border-radius: 50%; background: var(--line); }
.sync-label { margin-left: auto; display: flex; align-items: center; gap: 5px; }
.sync-label svg { width: 12px; height: 12px; }
.cinema-art { height: 292px; display: block; position: relative; overflow: hidden; border-radius: 10px; background: #171719; color: #f4f4f5; }
.cinema-art::before { content: ''; position: absolute; inset: 0; background-image: linear-gradient(#ffffff06 1px, transparent 1px), linear-gradient(90deg, #ffffff06 1px, transparent 1px); background-size: 34px 34px; }
.orbit { position: absolute; width: 270px; height: 270px; top: -72px; right: -46px; border-radius: 50%; background: repeating-radial-gradient(ellipse, transparent 0 6px, #d1d1dc2b 6.5px 7px); transform: rotate(-28deg) scaleX(1.35); }
.orbit-two { width: 180px; height: 180px; left: -70px; right: auto; top: 190px; opacity: .5; }
.film-label { position: absolute; left: 24px; top: 24px; color: #c9c9d0; font-size: 8px; letter-spacing: 2.5px; }
.scene-title { position: absolute; left: 24px; bottom: 53px; font-size: 28px; font-weight: 500; letter-spacing: -1px; }
.film-index { position: absolute; left: 24px; bottom: 28px; font-size: 8px; letter-spacing: 1.5px; color: #a8a8b0; }
.play-button { position: absolute; top: 46%; left: 47%; width: 52px; height: 52px; display: grid; place-items: center; border: 1px solid #ffffff45; background: #ffffff0e; border-radius: 50%; transition: background .2s; }
.cinema-art:hover .play-button { background: #ffffff24; }
.play-button svg { width: 23px; height: 23px; margin-right: 4px; }
.preview-timeline { display: flex; align-items: center; gap: 11px; font-size: 8px; color: var(--muted); padding: 16px 3px 8px; }
.preview-timeline > div { height: 2px; background: var(--soft); flex: 1; }
.preview-timeline i { display: block; width: 31%; height: 2px; background: var(--text); }
.preview-bottom { display: flex; align-items: center; gap: 12px; padding: 15px 3px 18px; }
.avatars { display: flex; padding-left: 5px; }
.avatars span { display: grid; place-items: center; width: 25px; height: 25px; border: 2px solid var(--surface); margin-left: -5px; border-radius: 50%; background: var(--soft); font-size: 8px; }
.avatars span:nth-child(2) { background: var(--text); color: var(--inverse); }
.preview-bottom p { font-size: 10px; color: var(--muted); }
.preview-bottom > svg { margin-left: auto; width: 15px; color: var(--muted); }
.floating-note { position: absolute; bottom: 30px; right: -25px; display: flex; align-items: center; gap: 13px; background: var(--surface); border: 1px solid var(--line); border-radius: 12px; padding: 16px 20px; box-shadow: var(--shadow); }
.floating-note > svg { width: 19px; }
.floating-note strong, .floating-note span:not(.note-dot) { display: block; font-size: 11px; }
.floating-note strong { font-weight: 500; }
.floating-note span:not(.note-dot) { color: var(--muted); margin-top: 3px; }
.note-dot { color: var(--text); margin-left: 20px; margin-right: 0; }
.hero-scene figcaption { font-size: 8px; color: var(--muted); position: absolute; bottom: 6px; left: 10px; letter-spacing: .4px; }
.promise-strip { display: flex; align-items: center; justify-content: space-between; padding: 26px 20px; border-block: 1px solid var(--line); color: var(--muted); }
.promise-strip span { display: flex; align-items: center; gap: 12px; font-size: 12px; }
.promise-strip svg { width: 18px; }
.section-block { padding-block: 112px; }
.section-heading { display: flex; align-items: flex-end; justify-content: space-between; gap: 28px; margin-bottom: 42px; }
h2 { font-size: clamp(28px, 3.1vw, 40px); line-height: 1.4; margin-top: 18px; }
.section-heading > p, .section-description { color: var(--muted); font-size: 13px; line-height: 2; }
.feature-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 18px; }
.feature-card { border: 1px solid var(--line); border-radius: 16px; background: var(--surface); padding: 27px; position: relative; overflow: hidden; }
.feature-number { position: absolute; top: 27px; right: 27px; color: var(--muted); font-size: 10px; letter-spacing: 1px; }
.feature-icon { width: 24px; height: 24px; margin-bottom: 26px; }
.feature-card h3 { font-size: 22px; line-height: 1.5; letter-spacing: -.5px; }
.feature-card > p { font-size: 12px; line-height: 1.9; color: var(--muted); margin-top: 14px; min-height: 68px; }
.sync-sketch, .chat-sketch, .room-sketch { margin-top: 29px; min-height: 90px; }
.sync-sketch { display: flex; gap: 13px; align-items: center; }
.sync-sketch > div { flex: 1; min-width: 0; border: 1px solid var(--line); padding: 19px 9px; border-radius: 7px; font-size: 8px; color: var(--muted); background: var(--bg); }
.sync-sketch i { display: block; height: 3px; margin-top: 14px; background: linear-gradient(90deg, var(--text) 58%, var(--line) 58%); }
.sync-sketch svg { width: 16px; }
.chat-sketch { display: flex; flex-direction: column; gap: 9px; align-items: flex-start; }
.chat-sketch > span { border: 1px solid var(--line); border-radius: 8px 8px 8px 2px; padding: 10px 12px; font-size: 10px; }
.chat-sketch > span:last-child { align-self: flex-end; background: var(--text); color: var(--inverse); border-color: var(--text); border-radius: 8px 8px 2px 8px; }
.room-sketch { border: 1px solid var(--line); border-radius: 10px; padding: 17px 12px; display: flex; gap: 10px; align-items: center; background: var(--bg); }
.room-sketch div { flex: 1; min-width: 0; }
.room-sketch strong { display: block; font-size: 10px; font-weight: 550; }
.room-sketch span { display: block; font-size: 9px; color: var(--muted); margin-top: 3px; }
.room-sketch > svg { width: 16px; }
.sources-band { border-block: 1px solid var(--line); background: var(--soft); padding-block: 86px; }
.sources-layout { display: grid; grid-template-columns: 1fr 1fr; align-items: center; gap: 100px; }
.sources-layout .section-description { margin-top: 22px; }
.sources-layout .text-link { margin-top: 30px; }
.source-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.source-grid > div { display: flex; flex-direction: column; padding: 23px; min-height: 142px; border: 1px solid var(--line); border-radius: 13px; background: var(--surface); }
.source-mark { display: grid; place-items: center; width: 30px; height: 30px; font-weight: 650; font-size: 23px; margin-bottom: 16px; }
svg.source-mark { padding: 3px; }
.source-grid strong { font-size: 13px; font-weight: 550; }
.source-grid small { color: var(--muted); font-size: 10px; margin-top: 4px; }
.steps { list-style: none; display: grid; grid-template-columns: repeat(3, 1fr); gap: 32px; padding: 0; margin: 0; counter-reset: step; }
.steps > li { padding-top: 24px; border-top: 1px solid var(--line); }
.steps span { font-size: 11px; color: var(--muted); letter-spacing: 2px; }
.steps h3 { font-size: 20px; margin: 19px 0 9px; }
.steps p { font-size: 12px; color: var(--muted); }
.plus-section { display: grid; grid-template-columns: 1fr 1fr; gap: 90px; align-items: center; padding-bottom: 110px; }
.plus-art { min-height: 305px; position: relative; overflow: hidden; background: linear-gradient(125deg, #303034, #101012 64%, #29292e); border: 1px solid #74747d; color: #f4f4f7; border-radius: 24px; padding: 29px; transform: rotate(-3deg); box-shadow: var(--shadow); }
.plus-art::after { content: ''; width: 210px; height: 210px; position: absolute; right: -18px; top: -38px; border-radius: 50%; border: 1px solid #ffffff26; box-shadow: 0 0 0 12px #ffffff07, 0 0 0 24px #ffffff07, 0 0 0 36px #ffffff07; }
.plus-art > span { display: block; font-size: 9px; letter-spacing: 2px; color: #c2c2cb; }
.plus-art > strong { display: block; font-size: 59px; letter-spacing: 9px; font-weight: 500; margin-top: 45px; }
.plus-art > svg { position: absolute; top: 35px; right: 32px; width: 30px; height: 30px; }
.plus-art p { position: absolute; bottom: 27px; font-size: 11px; color: #c2c2cb; }
.plus-copy > p:not(.eyebrow) { font-size: 12px; color: var(--muted); line-height: 2; margin-top: 22px; }
.plus-copy > p strong { color: var(--text); font-weight: 550; }
.plus-copy ul { list-style: none; padding: 0; margin: 23px 0 28px; }
.plus-copy li { display: flex; gap: 9px; align-items: center; font-size: 12px; margin-top: 9px; }
.plus-copy li svg { width: 14px; height: 14px; }
.faq-section { border-top: 1px solid var(--line); display: grid; grid-template-columns: 1fr 1.4fr; gap: 80px; }
.faq-list details { border-bottom: 1px solid var(--line); }
.faq-list summary { display: flex; justify-content: space-between; align-items: center; gap: 16px; padding: 21px 0; font-size: 14px; cursor: pointer; list-style: none; }
.faq-list summary::-webkit-details-marker { display: none; }
.faq-list summary > span { color: var(--muted); font-size: 18px; font-weight: 300; }
.faq-list details[open] summary > span { transform: rotate(45deg); }
.faq-list details p { color: var(--muted); font-size: 12px; line-height: 2; padding-bottom: 22px; }
.closing { text-align: center; padding: 64px 24px 86px; border: 1px solid var(--line); border-radius: 24px; background: radial-gradient(ellipse at top, var(--soft), var(--bg) 65%); }
.closing h2 { font-size: 42px; margin-bottom: 27px; }
.closing-login { display: block; font-size: 11px; color: var(--muted); margin-top: 18px; }
.site-footer { display: flex; gap: 28px; align-items: center; padding-block: 49px; }
.site-footer .brand > span { font-size: 17px; }
.site-footer .brand small { font-size: 8px; }
.site-footer > p { color: var(--muted); font-size: 11px; }
.site-footer nav { margin-left: auto; display: flex; gap: 20px; color: var(--muted); font-size: 11px; }
@media (max-width: 1100px) {
  .site-header { padding-inline: 32px; gap: 20px; }
  .header-nav { gap: 17px; }
  .header-actions { gap: 15px; }
  .hero { gap: 35px; padding-top: 65px; }
  .section-width { width: calc(100% - 64px); }
  .hero h1 { font-size: 47px; }
  .cinema-art { height: 260px; }
  .scene-title { font-size: 22px; }
  .floating-note { right: -10px; }
  .feature-card { padding: 22px; }
  .feature-card h3 { font-size: 19px; }
  .sources-layout, .plus-section { gap: 55px; }
}
@media (max-width: 1000px) {
  .header-nav { display: none; }
  .header-actions { margin-left: auto; }
  .menu-button { display: flex; }
  .mobile-menu { top: 90px; }
}
@media (max-width: 760px) {
  .mobile-menu { top: 80px; }
  html { scroll-padding-top: 30px; }
  .site-header { height: 80px; padding-inline: 22px; gap: 14px; }
  .header-nav { display: none; }
  .header-actions { margin-left: auto; gap: 14px; }
  .menu-button { display: flex; }
  .brand > span { font-size: 19px; }
  .brand img { width: 32px; height: 32px; }
  .brand { gap: 9px; }
  .brand small { font-size: 7px; letter-spacing: 1.7px; margin-top: 5px; }
  .section-width { width: calc(100% - 44px); }
  .hero { display: block; padding: 45px 0 38px; min-height: auto; }
  .hero-copy { text-align: center; }
  .hero h1 { font-size: clamp(39px, 8.5vw, 56px); margin-top: 23px; }
  .hero-description { font-size: 13px; margin-top: 21px; }
  .hero-actions { justify-content: center; gap: 20px; margin-top: 26px; }
  .hero-note { justify-content: center; flex-wrap: wrap; font-size: 9px; margin-top: 22px; }
  .hero-scene { max-width: 500px; margin: 47px auto 0; padding-bottom: 58px; }
  .room-preview { transform: none; padding-inline: 10px; }
  .cinema-art { height: 246px; }
  .scene-glow { inset: -45px -15px 0; }
  .floating-note { right: 7px; bottom: 24px; padding: 12px 16px; }
  .promise-strip { display: grid; grid-template-columns: 1fr 1fr; padding: 24px 7px; gap: 24px 15px; }
  .promise-strip span { gap: 9px; font-size: 11px; }
  .section-block { padding-block: 68px; }
  .section-heading { display: block; margin-bottom: 28px; }
  .section-heading > p, .section-heading > a { margin-top: 20px; }
  h2 { font-size: 29px; margin-top: 14px; }
  .feature-grid { grid-template-columns: 1fr; gap: 15px; }
  .feature-card { padding: 26px; }
  .feature-card h3 { font-size: 22px; }
  .feature-card > p { min-height: 0; }
  .feature-card h3 br { display: none; }
  .sync-sketch, .chat-sketch, .room-sketch { margin-top: 22px; }
  .sources-band { padding-block: 57px; }
  .sources-layout { grid-template-columns: 1fr; gap: 34px; }
  .source-grid > div { padding: 19px; }
  .steps { grid-template-columns: 1fr; gap: 23px; }
  .steps > li { padding-top: 20px; }
  .steps h3 { margin-top: 10px; }
  .plus-section { grid-template-columns: 1fr; gap: 36px; padding-bottom: 65px; }
  .plus-art { min-height: 258px; margin-inline: 5px; }
  .plus-art > strong { margin-top: 30px; font-size: 53px; }
  .plus-copy h2 br { display: none; }
  .faq-section { grid-template-columns: 1fr; gap: 25px; }
  .faq-section h2 br { display: none; }
  .faq-list summary { font-size: 13px; }
  .closing { padding: 48px 16px 55px; }
  .closing h2 { font-size: 32px; }
  .site-footer { flex-wrap: wrap; gap: 22px; padding-block: 35px; }
  .site-footer > p { margin-left: auto; font-size: 9px; }
  .site-footer nav { flex-basis: 100%; justify-content: center; margin-top: 7px; }
}
@media (max-width: 360px) {
  .site-header { padding-inline: 16px; }
  .header-actions { gap: 10px; }
  .button.small { padding-inline: 11px; }
  .button.small svg { display: none; }
  .section-width { width: calc(100% - 32px); }
  .hero-actions { gap: 16px; }
  .hero-actions .button { gap: 15px; padding-inline: 18px; }
  .hero-actions .text-link { font-size: 11px; gap: 5px; }
  .scene-title { font-size: 20px; }
  .cinema-art { height: 225px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
}