:root {
  --paper: #f7f4ef;
  --paper-deep: #eee7dc;
  --ink: #24211e;
  --muted: #77736c;
  --line: #ded7ce;
  --china: #8b4513;
  --china-soft: #f3e8dc;
  --west: #2f4a5f;
  --west-soft: #e8eef1;
  --amber: #c47e3b;
  --white: #fffdf9;
  --shadow: 0 18px 50px rgba(68, 51, 35, .09);
  font-family: 'Noto Sans SC', system-ui, sans-serif;
  color: var(--ink);
  background: var(--paper);
  font-synthesis: none;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; min-width: 320px; background: var(--paper); }
button, input, select { font: inherit; }
a { color: inherit; text-decoration: none; }
button, a { -webkit-tap-highlight-color: transparent; }

.site-frame { min-height: 100vh; overflow: hidden; }
.site-header { height: 78px; padding: 0 clamp(20px, 5vw, 76px); display: flex; align-items: center; justify-content: space-between; gap: 28px; border-bottom: 1px solid rgba(139, 69, 19, .12); background: rgba(247, 244, 239, .92); backdrop-filter: blur(16px); position: sticky; top: 0; z-index: 20; }
.brand { display: flex; gap: 11px; align-items: center; min-width: 190px; }
.brand > span:last-child { display: grid; gap: 2px; }
.brand strong { font-family: 'Noto Serif SC', serif; font-size: 17px; letter-spacing: .08em; }
.brand small { color: var(--muted); font-size: 10px; letter-spacing: .16em; }
.brand-mark { width: 34px; height: 34px; border: 1px solid var(--china); border-radius: 10px; display: block; position: relative; background: var(--white); overflow: hidden; }
.brand-mark i, .brand-mark b { position: absolute; display: block; height: 4px; border-radius: 99px; transform: rotate(-42deg); }
.brand-mark i { width: 25px; left: 3px; top: 13px; background: var(--china); }
.brand-mark b { width: 24px; right: 1px; top: 19px; background: var(--west); }
.main-nav { display: flex; align-items: center; gap: clamp(14px, 2vw, 32px); }
.nav-link { font-size: 13px; color: var(--muted); padding: 28px 0 25px; border-bottom: 2px solid transparent; white-space: nowrap; }
.nav-link:hover, .nav-link.is-active { color: var(--ink); border-color: var(--amber); }
.install-button { border: 1px solid var(--china); background: transparent; color: var(--china); border-radius: 999px; padding: 9px 16px; cursor: pointer; font-size: 12px; white-space: nowrap; }
.install-button:hover { background: var(--china); color: var(--white); }
.install-button:disabled { opacity: .6; cursor: default; }

main { min-height: calc(100vh - 180px); }
.hero-home { max-width: 1280px; margin: 0 auto; min-height: 650px; padding: 100px clamp(24px, 6vw, 90px) 82px; display: grid; grid-template-columns: minmax(0, 1.08fr) minmax(360px, .92fr); align-items: center; gap: 54px; }
.hero-copy { max-width: 670px; }
.eyebrow { margin: 0 0 16px; color: var(--amber); text-transform: uppercase; letter-spacing: .18em; font-size: 11px; font-weight: 700; }
h1, h2, h3, p { margin-top: 0; }
h1, h2, h3 { font-family: 'Noto Serif SC', serif; }
.hero-home h1 { font-size: clamp(42px, 6.5vw, 76px); line-height: 1.16; letter-spacing: -.06em; margin-bottom: 28px; font-weight: 800; }
.hero-home h1 em { color: var(--china); font-style: normal; }
.hero-lede { color: #5f5a53; font-size: 17px; line-height: 2; max-width: 590px; margin-bottom: 34px; }
.hero-actions { display: flex; align-items: center; flex-wrap: wrap; gap: 12px; }
.button { display: inline-flex; align-items: center; gap: 16px; padding: 13px 20px; border-radius: 4px; font-size: 13px; transition: transform .2s, background .2s; }
.button:hover { transform: translateY(-2px); }
.button-primary { background: var(--china); color: white; }
.button-primary:hover { background: #6e340f; }
.button-quiet { border: 1px solid var(--line); color: var(--muted); background: rgba(255,255,255,.34); }
.button-dark { background: var(--ink); color: var(--white); }
.hero-note { margin-top: 42px; color: var(--muted); font-size: 12px; display: flex; align-items: center; gap: 8px; }
.signal-dot { width: 7px; height: 7px; border-radius: 50%; background: #6f9c71; box-shadow: 0 0 0 5px rgba(111,156,113,.12); }
.hero-visual { min-height: 420px; position: relative; display: grid; place-items: center; }
.hero-visual::before { content: ''; position: absolute; width: 330px; height: 330px; border: 1px solid rgba(196,126,59,.25); border-radius: 50%; }
.orbit { position: absolute; width: 285px; height: 285px; border: 1px dashed rgba(47,74,95,.26); border-radius: 50%; animation: drift 18s linear infinite; }
.orbit::after { content: ''; position: absolute; width: 9px; height: 9px; border-radius: 50%; background: var(--amber); left: 23px; top: 46px; }
.orbit-china { transform: rotate(20deg); border-color: rgba(139,69,19,.32); }
.orbit-west { width: 212px; height: 212px; transform: rotate(-31deg); animation-duration: 15s; }
.orbit span, .orbit b, .orbit i, .orbit strong, .orbit small { position: absolute; font-style: normal; font-weight: 600; background: var(--paper); padding: 2px 5px; }
.orbit span { left: 12px; top: 130px; color: var(--china); font-family: serif; font-size: 28px; }
.orbit b { left: 37px; top: 48px; color: var(--china); font-size: 12px; }
.orbit i { right: 1px; top: 128px; color: var(--china); font-size: 11px; }
.orbit strong { right: 40px; bottom: 26px; color: var(--china); font-size: 12px; }
.orbit small { left: 119px; bottom: -4px; color: var(--china); font-size: 10px; }
.orbit-west span { left: 105px; top: -11px; color: var(--west); font-family: serif; font-size: 27px; }
.orbit-west b { left: -24px; top: 85px; color: var(--west); font-size: 11px; }
.orbit-west i { right: -40px; top: 83px; color: var(--west); font-size: 11px; }
.orbit-west strong { right: 35px; bottom: -14px; color: var(--west); font-size: 11px; }
.orbit-west small { display: none; }
.orbit-center { width: 100px; height: 100px; border-radius: 50%; display: grid; place-content: center; text-align: center; color: var(--white); background: var(--ink); font-family: 'Noto Serif SC',serif; font-size: 21px; line-height: 1.45; z-index: 2; box-shadow: var(--shadow); }
.orbit-center small { font: 11px 'Noto Sans SC', sans-serif; letter-spacing: .18em; color: #d5cec3; }
@keyframes drift { to { transform: rotate(380deg); } }
@keyframes driftReverse { to { transform: rotate(-391deg); } }

.section { max-width: 1280px; padding: 75px clamp(24px, 6vw, 90px); margin: 0 auto; }
.section-tight { max-width: 1180px; margin: 0 auto; padding: 30px clamp(20px, 4vw, 42px) 80px; }
.section-heading { display: flex; align-items: end; justify-content: space-between; gap: 30px; margin-bottom: 30px; }
.section-heading h2 { font-size: clamp(28px, 4vw, 44px); letter-spacing: -.04em; margin: 0; }
.section-intro { color: var(--muted); font-size: 13px; max-width: 280px; line-height: 1.8; margin: 0; }
.text-link { color: var(--china); font-size: 13px; white-space: nowrap; }
.text-link span { margin-left: 9px; }
.featured-section { border-top: 1px solid var(--line); }
.featured-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 15px; }
.featured-card { min-width: 0; background: var(--white); border: 1px solid var(--line); transition: box-shadow .2s, transform .2s; }
.featured-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
.featured-image { aspect-ratio: 1.25; background: var(--china-soft); position: relative; overflow: hidden; }
.featured-image img { width: 100%; height: 100%; object-fit: cover; display: block; filter: saturate(.82); }
.featured-image::after { content: ''; position: absolute; inset: 0; background: linear-gradient(180deg, transparent 55%, rgba(26,23,20,.46)); }
.featured-image.is-empty { display: grid; place-items: center; color: var(--muted); font-size: 12px; }
.featured-image i { position: absolute; left: 13px; bottom: 11px; z-index: 1; color: white; font-style: normal; font-family: 'Noto Serif SC',serif; font-size: 22px; }
.featured-card-body { min-height: 104px; padding: 16px; position: relative; }
.featured-card-body > div { display: flex; justify-content: space-between; align-items: baseline; gap: 6px; }
.featured-card h3 { margin: 0; font-size: 17px; }
.featured-card-body span { color: var(--muted); font-size: 10px; }
.featured-card-body p { margin: 12px 0 0; color: var(--muted); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; font-size: 11px; }
.featured-card-body > b { position: absolute; right: 15px; bottom: 15px; color: var(--china); font-size: 20px; font-weight: 400; }
.group-overview { background: var(--paper-deep); max-width: none; padding-left: max(24px, calc((100% - 1100px) / 2)); padding-right: max(24px, calc((100% - 1100px) / 2)); }
.group-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1px; border: 1px solid var(--line); background: var(--line); }
.group-tile { min-height: 145px; padding: 19px; background: var(--paper); display: flex; flex-direction: column; position: relative; transition: background .2s; }
.group-tile:hover { background: var(--white); }
.group-tile > span { color: var(--muted); font: 12px 'Noto Sans SC'; }
.group-tile strong { font: 600 21px 'Noto Serif SC'; margin-top: 21px; }
.group-tile small { margin-top: 6px; color: var(--muted); font-size: 11px; }
.group-tile b { position: absolute; right: 17px; bottom: 15px; color: var(--amber); font-size: 19px; font-weight: 400; }
.group-1 strong, .group-4 strong { color: var(--west); }
.method-section { display: grid; grid-template-columns: 1fr 1.55fr; gap: 70px; align-items: start; }
.method-callout h2 { font-size: 33px; line-height: 1.45; margin-bottom: 27px; }
.method-list { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; padding-top: 17px; }
.method-list article { border-top: 2px solid var(--amber); padding-top: 15px; }
.method-list article:nth-child(2) { border-color: var(--west); }
.method-list article:nth-child(3) { border-color: #6d7b61; }
.method-list span { color: var(--muted); font-size: 11px; }
.method-list h3 { font-size: 18px; margin: 22px 0 8px; }
.method-list p { color: var(--muted); font-size: 12px; line-height: 1.8; margin: 0; }

.page-hero { max-width: 1180px; margin: 0 auto; }
.compact-hero { padding: 80px 42px 35px; }
.compact-hero h1 { font-size: clamp(34px, 5vw, 59px); letter-spacing: -.055em; margin: 0 0 17px; }
.compact-hero > p:last-child { color: var(--muted); max-width: 620px; line-height: 1.9; font-size: 15px; margin: 0; }
.toolbar { border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); padding: 16px 0; display: flex; justify-content: space-between; align-items: center; gap: 14px; margin-bottom: 26px; }
.toolbar-group { display: flex; gap: 22px; align-items: center; }
.toolbar label { color: var(--muted); font-size: 12px; display: flex; gap: 9px; align-items: center; }
.toolbar select { border: 0; border-bottom: 1px solid var(--line); background: transparent; padding: 6px 22px 6px 3px; color: var(--ink); outline: none; }
.view-switch { display: inline-flex; border: 1px solid var(--line); }
.view-switch button { border: 0; background: transparent; padding: 7px 12px; font-size: 11px; color: var(--muted); cursor: pointer; }
.view-switch button + button { border-left: 1px solid var(--line); }
.view-switch .is-active { background: var(--ink); color: white; }
.timeline-list { position: relative; padding-left: 76px; }
.timeline-list::before { content: ''; position: absolute; left: 23px; top: 0; bottom: 0; width: 1px; background: var(--line); }
.timeline-group-heading { display: flex; align-items: center; gap: 16px; margin: 31px 0 12px -76px; position: relative; }
.timeline-group-heading > span { width: 47px; height: 47px; border-radius: 50%; background: var(--paper-deep); border: 1px solid var(--line); position: relative; z-index: 1; }
.timeline-group-heading > span::after { content: ''; width: 9px; height: 9px; border-radius: 50%; background: var(--amber); position: absolute; left: 18px; top: 18px; }
.timeline-group-heading b { font-family: 'Noto Serif SC',serif; font-size: 19px; }
.timeline-group-heading small { display: block; color: var(--muted); font-size: 11px; margin-top: 4px; }
.period-card { display: flex; gap: 17px; margin: 0 0 12px -76px; padding: 18px 21px 18px 0; border-bottom: 1px solid var(--line); position: relative; }
.period-card:hover .period-card-main { background: var(--white); box-shadow: 0 9px 25px rgba(63,48,33,.06); }
.period-marker { width: 47px; display: grid; align-content: start; justify-items: center; color: var(--muted); font-size: 9px; position: relative; z-index: 1; }
.period-marker i { width: 12px; height: 12px; border-radius: 50%; background: var(--paper); border: 3px solid var(--amber); margin-top: 12px; }
.period-card-main { flex: 1; min-width: 0; padding: 4px 15px 12px; border-radius: 2px; transition: background .2s, box-shadow .2s; }
.period-card-head { display: flex; align-items: start; justify-content: space-between; gap: 16px; }
.period-card h3 { font-size: 20px; margin: 0 0 5px; }
.year-label { color: var(--muted); font-size: 11px; }
.card-tags { display: flex; gap: 5px; flex-wrap: wrap; justify-content: end; }
.material-badge, .cluster-label { padding: 4px 7px; border: 1px solid var(--line); color: var(--muted); font-size: 10px; white-space: nowrap; }
.material-badge.ready { border-color: #b7c8bd; color: #527162; background: #edf5ef; }
.cluster-label { border: 0; color: var(--west); background: var(--west-soft); }
.period-card-main > p { color: #5f5a53; font-size: 13px; line-height: 1.8; margin: 12px 0; }
.period-card-main > p span { color: var(--amber); }
.card-foot { display: flex; justify-content: space-between; color: var(--muted); font-size: 10px; }
.card-foot b { color: var(--china); font-weight: 500; }
.card-foot strong { font-size: 15px; font-weight: 400; margin-left: 5px; }
.period-card.is-preview .period-marker i { border-color: #b7b1a8; }
.period-card.is-preview .period-card-main { opacity: .83; }
.cluster-list { display: grid; gap: 22px; }
.cluster-board { border: 1px solid var(--line); background: var(--white); padding: 25px; }
.cluster-board > header { display: flex; justify-content: space-between; gap: 30px; align-items: end; border-bottom: 1px solid var(--line); padding-bottom: 18px; margin-bottom: 18px; }
.cluster-board > header .eyebrow { margin-bottom: 6px; }
.cluster-board h2 { margin: 0; font-size: 26px; }
.cluster-board > header > p { color: var(--muted); font-size: 12px; max-width: 360px; line-height: 1.7; margin: 0; }
.cluster-members { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; }
.cluster-northern-southern .cluster-members { grid-template-columns: repeat(2, 1fr); }
.cluster-song-concurrent .cluster-members { grid-template-columns: repeat(5, 1fr); }
.cluster-member { min-height: 112px; border: 1px solid var(--line); padding: 15px; display: flex; flex-direction: column; position: relative; transition: border-color .2s, transform .2s; }
.cluster-member:hover { border-color: var(--amber); transform: translateY(-2px); }
.cluster-member strong { font: 600 18px 'Noto Serif SC'; }
.cluster-member span { color: var(--muted); font-size: 10px; margin-top: 5px; }
.cluster-member small { color: var(--west); margin-top: auto; font-size: 11px; }
.cluster-member b { position: absolute; right: 12px; top: 12px; color: var(--amber); font-weight: 400; }

.search-shell { max-width: 900px; }
.search-box { background: var(--white); border: 1px solid var(--line); padding: 16px 18px; display: flex; align-items: center; gap: 12px; }
.search-box > span { color: var(--amber); font-size: 22px; }
.search-box input { border: 0; outline: 0; background: transparent; width: 100%; font-size: 16px; color: var(--ink); }
.search-box input::placeholder { color: #aaa39a; }
.search-box kbd { color: var(--muted); font-size: 10px; border: 1px solid var(--line); padding: 4px 6px; white-space: nowrap; }
.search-meta { display: flex; justify-content: space-between; color: var(--muted); font-size: 11px; margin: 14px 0 28px; }
.search-meta a { color: var(--china); }
.search-results .period-card { margin-left: 0; padding-left: 0; }
.search-results .period-marker { display: none; }

.period-top { max-width: 1180px; margin: 0 auto; padding: 48px 42px 0; }
.breadcrumb { display: flex; gap: 10px; color: var(--muted); font-size: 11px; margin-bottom: 35px; }
.breadcrumb a { color: var(--china); }
.period-top-row { display: flex; justify-content: space-between; align-items: end; gap: 30px; }
.period-top h1 { margin: 0 0 8px; font-size: clamp(40px, 6vw, 68px); letter-spacing: -.06em; }
.period-years { color: var(--muted); font-size: 14px; }
.period-navigation { display: flex; gap: 20px; }
.period-navigation a { color: var(--china); font-size: 12px; }
.period-navigation span { color: var(--muted); }
.status-banner { margin-top: 35px; padding: 11px 13px; border-left: 3px solid var(--amber); background: var(--paper-deep); color: var(--muted); font-size: 11px; }
.status-banner span { color: var(--ink); font-weight: 600; }
.status-banner.status-ready { border-color: #6d9d81; background: #edf4ee; }
.period-layout { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; align-items: start; }
.side-panel { background: var(--white); border: 1px solid var(--line); min-width: 0; }
.china-panel { border-top: 4px solid var(--china); }
.west-panel { border-top: 4px solid var(--west); }
.panel-heading { display: flex; justify-content: space-between; padding: 23px 25px 0; }
.side-kicker { color: var(--muted); letter-spacing: .14em; text-transform: uppercase; font-size: 10px; font-weight: 700; }
.panel-icon { width: 28px; height: 28px; border-radius: 50%; display: grid; place-items: center; background: var(--china-soft); color: var(--china); font-family: serif; }
.west-panel .panel-icon { background: var(--west-soft); color: var(--west); }
.side-panel > h2 { padding: 0 25px; margin: 18px 0 0; font-size: 27px; }
.panel-years { padding: 0 25px; color: var(--muted); font-size: 11px; margin: 5px 0 16px; }
.side-summary { padding: 0 25px; color: #5f5a53; line-height: 1.9; font-size: 13px; min-height: 76px; }
.illustration-card { margin: 22px 25px 0; }
.illustration-card button { padding: 0; border: 0; background: var(--paper-deep); display: block; width: 100%; position: relative; cursor: zoom-in; }
.illustration-card img { width: 100%; aspect-ratio: 1.45; object-fit: cover; display: block; }
.illustration-card .zoom-hint { position: absolute; right: 9px; bottom: 8px; background: rgba(26,23,20,.7); color: white; padding: 5px 7px; font-size: 9px; opacity: 0; transition: opacity .2s; }
.illustration-card button:hover .zoom-hint { opacity: 1; }
.illustration-card figcaption { display: grid; gap: 5px; padding: 10px 0 4px; }
.illustration-card figcaption strong { font-size: 10px; }
.illustration-card figcaption span, .illustration-card figcaption small { color: var(--muted); font-size: 10px; line-height: 1.6; }
.illustration-card figcaption small { color: #999188; }
.illustration-placeholder { margin: 22px 25px 0; min-height: 203px; border: 1px dashed #cfc7bc; background: repeating-linear-gradient(-45deg, rgba(245,241,234,.5), rgba(245,241,234,.5) 8px, rgba(238,232,222,.7) 8px, rgba(238,232,222,.7) 16px); display: grid; place-items: center; align-content: center; text-align: center; padding: 20px; }
.placeholder-mark { width: 37px; height: 37px; display: grid; place-items: center; border: 1px solid var(--amber); color: var(--amber); border-radius: 50%; font-family: serif; margin-bottom: 10px; }
.illustration-placeholder strong { font: 600 16px 'Noto Serif SC'; }
.illustration-placeholder p { color: var(--muted); font-size: 11px; max-width: 220px; line-height: 1.7; margin: 7px 0 0; }
.concurrent-box { margin: 23px 25px 25px; padding-top: 17px; border-top: 1px solid var(--line); display: grid; gap: 8px; }
.concurrent-box > span { color: var(--muted); font-size: 10px; }
.concurrent-box > a { color: var(--china); font-size: 12px; }
.chips { display: flex; gap: 7px; flex-wrap: wrap; }
.chips a { border: 1px solid var(--line); padding: 5px 8px; color: var(--west); font-size: 10px; }
.event-list { padding: 0 25px; }
.event-item { display: grid; grid-template-columns: 91px 1fr; gap: 14px; padding: 16px 0; border-top: 1px solid var(--line); }
.event-date { color: var(--west); font-size: 10px; line-height: 1.5; padding-top: 3px; }
.event-item h3 { margin: 0 0 7px; font-size: 16px; }
.event-item p { color: #5f5a53; font-size: 12px; line-height: 1.75; margin: 0; }
.west-panel .illustration-card { margin-top: 7px; }
.closing-note { padding: 0 25px 25px; color: var(--muted); font-size: 11px; line-height: 1.7; }
.commentary-block { grid-column: 1 / -1; background: var(--ink); color: var(--white); padding: 29px 35px 32px; }
.commentary-heading { display: flex; justify-content: space-between; align-items: start; gap: 20px; }
.commentary-heading .side-kicker { color: #c5b7a6; }
.commentary-heading h2 { margin: 10px 0 0; font-size: 24px; }
.commentary-status { color: #c9dabb; border: 1px solid rgba(201,218,187,.5); padding: 5px 8px; font-size: 10px; }
.commentary-status.is-muted { color: #b5ada4; border-color: #5f5a53; }
.commentary-body { max-width: 880px; margin: 23px 0 11px; color: #ddd5ca; font-family: 'Noto Serif SC',serif; font-size: 15px; line-height: 2; }
.commentary-author { color: #9f968c; font-size: 10px; margin: 0; }
.commentary-placeholder { border: 1px solid rgba(255,255,255,.17); padding: 22px; margin-top: 25px; max-width: 670px; }
.commentary-placeholder strong { font-family: 'Noto Serif SC',serif; font-size: 17px; }
.commentary-placeholder p { color: #bcb3a9; font-size: 12px; line-height: 1.8; margin: 10px 0 15px; }
.commentary-placeholder a { color: #e8ba82; font-size: 11px; }
.uncertainty-alert { grid-column: 1 / -1; border: 1px solid #e3bd88; background: #fff8ec; padding: 17px 20px; display: flex; align-items: start; gap: 13px; }
.uncertainty-alert > span { width: 20px; height: 20px; border-radius: 50%; background: var(--amber); color: white; display: grid; place-items: center; font-weight: 700; font-size: 12px; flex: none; }
.uncertainty-alert strong { font-size: 12px; }
.uncertainty-alert p { color: #796d60; margin: 5px 0 0; font-size: 11px; line-height: 1.7; }
.uncertainty-alert a { color: var(--china); font-size: 10px; margin-left: auto; white-space: nowrap; padding-top: 3px; }
.period-bottom { max-width: 1110px; margin: 0 auto; padding: 0 25px 70px; display: flex; justify-content: space-between; align-items: center; color: var(--muted); font-size: 11px; }
.period-bottom a { color: var(--china); }

.about-grid { display: grid; grid-template-columns: 1.2fr .8fr; gap: 18px; }
.about-card { border: 1px solid var(--line); background: var(--white); padding: 29px; }
.about-card h2 { font-size: 26px; margin-bottom: 22px; }
.about-card > p:not(.eyebrow) { color: #655f58; font-size: 13px; line-height: 1.9; }
.about-wide { grid-column: 1 / -1; }
.principle-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.principle-grid > div { border-top: 2px solid var(--amber); padding-top: 12px; }
.principle-grid strong { font-family: 'Noto Serif SC',serif; font-size: 15px; }
.principle-grid p { color: var(--muted); font-size: 11px; line-height: 1.75; margin: 8px 0 0; }
.progress-stat { display: flex; align-items: baseline; gap: 12px; border-bottom: 1px solid var(--line); padding: 15px 0; }
.progress-stat strong { font: 700 34px 'Noto Serif SC'; color: var(--china); }
.progress-stat span { color: var(--muted); font-size: 12px; }
.muted { color: var(--muted) !important; font-size: 11px !important; }
.uncertainty-list { display: grid; grid-template-columns: repeat(2, 1fr); gap: 10px; }
.uncertainty-item { border: 1px solid var(--line); padding: 14px; display: flex; gap: 11px; align-items: start; transition: border-color .2s; }
.uncertainty-item:hover { border-color: var(--amber); }
.uncertainty-item > span { width: 20px; height: 20px; border-radius: 50%; display: grid; place-items: center; background: #f1dfc6; color: var(--china); font-size: 11px; flex: none; }
.uncertainty-item strong { font-family: 'Noto Serif SC',serif; font-size: 13px; }
.uncertainty-item p { color: var(--muted); font-size: 10px; line-height: 1.7; margin: 5px 0 0; }
.uncertainty-item b { margin-left: auto; color: var(--amber); font-weight: 400; }

.empty-state { text-align: center; padding: 70px 20px; border: 1px dashed var(--line); color: var(--muted); }
.empty-state > span { font-size: 31px; color: var(--amber); }
.empty-state h2 { color: var(--ink); margin: 12px 0 5px; font-size: 21px; }
.empty-state p { font-size: 12px; margin: 0; }
.lightbox { border: 0; background: rgba(21,19,17,.95); color: white; max-width: min(1000px, 92vw); padding: 23px; }
.lightbox::backdrop { background: rgba(21,19,17,.75); }
.lightbox img { max-width: 100%; max-height: 74vh; display: block; margin: 0 auto; }
.lightbox p { color: #d8d0c6; font-size: 11px; line-height: 1.6; margin: 13px 0 0; }
.lightbox-close { position: absolute; right: 8px; top: 2px; border: 0; background: transparent; color: white; font-size: 28px; cursor: pointer; }
.install-dialog { width: min(420px, calc(100vw - 36px)); border: 1px solid var(--line); background: var(--white); color: var(--ink); padding: 32px; box-shadow: var(--shadow); }
.install-dialog::backdrop { background: rgba(34, 29, 24, .45); }
.install-dialog h2 { font-size: 27px; margin: 0 0 13px; }
.install-dialog p:not(.eyebrow) { color: var(--muted); font-size: 13px; line-height: 1.9; margin-bottom: 23px; }
.install-dialog .lightbox-close { color: var(--ink); }
.site-footer { max-width: 1180px; border-top: 1px solid var(--line); margin: 0 auto; padding: 35px 42px 50px; display: flex; justify-content: space-between; gap: 30px; align-items: end; color: var(--muted); }
.footer-kicker { color: var(--ink); font-family: 'Noto Serif SC',serif; font-size: 15px; }
.site-footer p { font-size: 11px; margin: 7px 0 0; }
.footer-links { display: flex; gap: 18px; font-size: 11px; }
.footer-links a:hover { color: var(--china); }
.site-footer > small { font-size: 10px; text-align: right; }

@media (max-width: 900px) {
  .site-header { height: auto; min-height: 70px; flex-wrap: wrap; padding-top: 13px; padding-bottom: 0; gap: 8px 18px; }
  .main-nav { order: 3; width: 100%; overflow-x: auto; gap: 22px; }
  .nav-link { padding: 9px 0 14px; }
  .hero-home { grid-template-columns: 1fr; padding-top: 65px; }
  .hero-visual { min-height: 330px; }
  .featured-grid { grid-template-columns: repeat(2, 1fr); }
  .group-grid { grid-template-columns: repeat(3, 1fr); }
  .method-section { grid-template-columns: 1fr; gap: 20px; }
  .period-layout { grid-template-columns: 1fr; }
  .commentary-block, .uncertainty-alert { grid-column: auto; }
  .about-grid { grid-template-columns: 1fr; }
  .about-wide { grid-column: auto; }
}

@media (max-width: 600px) {
  .site-header { padding-left: 17px; padding-right: 17px; }
  .brand { min-width: 0; }
  .brand strong { font-size: 15px; }
  .install-button { padding: 8px 12px; }
  .hero-home { min-height: auto; padding: 61px 20px 55px; gap: 20px; }
  .hero-home h1 { font-size: 42px; }
  .hero-lede { font-size: 14px; line-height: 1.9; }
  .hero-visual { transform: scale(.8); margin: -20px 0; }
  .section { padding: 55px 20px; }
  .section-heading { align-items: start; flex-direction: column; gap: 14px; }
  .featured-grid { grid-template-columns: 1fr 1fr; gap: 8px; }
  .featured-card-body { padding: 11px; min-height: 92px; }
  .featured-card h3 { font-size: 15px; }
  .featured-card-body p { font-size: 10px; }
  .group-grid { grid-template-columns: 1fr 1fr; }
  .group-tile { min-height: 125px; padding: 14px; }
  .group-tile strong { font-size: 18px; margin-top: 15px; }
  .method-list { grid-template-columns: 1fr; gap: 18px; }
  .compact-hero { padding: 58px 20px 22px; }
  .compact-hero h1 { font-size: 39px; }
  .section-tight { padding-left: 20px; padding-right: 20px; }
  .toolbar { align-items: stretch; flex-direction: column; }
  .toolbar-group { justify-content: space-between; gap: 7px; }
  .toolbar label { flex: 1; justify-content: space-between; }
  .toolbar select { max-width: 105px; }
  .timeline-list { padding-left: 35px; }
  .timeline-list::before { left: 10px; }
  .timeline-group-heading, .period-card { margin-left: -35px; }
  .timeline-group-heading { gap: 10px; }
  .timeline-group-heading > span { width: 21px; height: 21px; }
  .timeline-group-heading > span::after { width: 7px; height: 7px; left: 6px; top: 6px; }
  .timeline-group-heading > div { flex: 1; }
  .timeline-group-heading b { font-size: 17px; }
  .period-marker { width: 21px; font-size: 8px; }
  .period-marker i { width: 10px; height: 10px; border-width: 2px; margin-top: 13px; }
  .period-card { gap: 8px; padding-right: 0; }
  .period-card-main { padding-left: 7px; }
  .period-card-head { display: block; }
  .card-tags { justify-content: start; margin-top: 9px; }
  .period-card-main > p { font-size: 12px; }
  .cluster-board { padding: 18px; }
  .cluster-board > header { display: block; }
  .cluster-board > header > p { margin-top: 12px; }
  .cluster-members, .cluster-song-concurrent .cluster-members { grid-template-columns: 1fr 1fr; }
  .cluster-member { min-height: 100px; }
  .period-top { padding: 32px 20px 0; }
  .period-top-row { display: block; }
  .period-top h1 { font-size: 48px; }
  .period-navigation { justify-content: space-between; margin-top: 22px; }
  .panel-heading, .side-panel > h2, .panel-years, .side-summary, .event-list { padding-left: 18px; padding-right: 18px; }
  .side-panel > h2 { font-size: 24px; }
  .illustration-card, .illustration-placeholder { margin-left: 18px; margin-right: 18px; }
  .concurrent-box { margin-left: 18px; margin-right: 18px; }
  .event-item { grid-template-columns: 1fr; gap: 4px; }
  .commentary-block { padding: 23px 18px; }
  .commentary-body { font-size: 14px; }
  .uncertainty-alert { display: grid; grid-template-columns: auto 1fr; }
  .uncertainty-alert a { grid-column: 2; margin-left: 0; }
  .period-bottom { padding: 0 20px 50px; }
  .period-bottom span { display: none; }
  .principle-grid, .uncertainty-list { grid-template-columns: 1fr; }
  .about-card { padding: 21px; }
  .site-footer { padding: 29px 20px 35px; display: grid; gap: 17px; }
  .site-footer > small { text-align: left; }
}