.site-header { position: sticky; top: 0; z-index: 20; background: rgba(227,243,252,.94); border-bottom: 1px solid transparent; backdrop-filter: blur(16px); transition: .2s ease; }
.site-header[data-elevated="true"] { border-color: var(--border); box-shadow: 0 8px 30px rgba(0,54,96,.06); }
.nav-shell { width: min(calc(100% - 40px), var(--content)); min-height: 70px; margin: auto; display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; font-size: .85rem; font-weight: 700; }
.brand-mark { padding: 6px 9px; color: var(--ink); background: var(--ustc-blue); border-radius: 6px; letter-spacing: .06em; }
.brand-copy { color: var(--ustc-blue-deep); }
.nav-links { display: flex; gap: 24px; }
.nav-links a { position: relative; color: var(--muted); font-size: .82rem; font-weight: 700; text-decoration: none; }
.nav-links a::after { content: ""; position: absolute; left: 0; right: 100%; bottom: -7px; height: 2px; background: var(--orange); transition: right .2s; }
.nav-links a:hover::after, .nav-links a:focus::after { right: 0; }
.nav-toggle { display: none; border: 0; color: var(--ink); background: var(--ustc-blue); border-radius: 8px; padding: 7px 10px; }

.hero { padding-top: clamp(72px, 10vw, 136px); text-align: center; }
.hero h1 { max-width: 1000px; margin: 20px auto 14px; color: var(--ustc-blue-deep); font-size: clamp(3.1rem, 8.5vw, 7.4rem); line-height: .91; letter-spacing: -.055em; }
.subtitle { max-width: 780px; margin: 0 auto 26px; color: var(--muted); font-size: clamp(1.05rem, 2.3vw, 1.38rem); line-height: 1.5; }
.authors { display: flex; flex-wrap: wrap; justify-content: center; gap: 6px 14px; margin-top: 26px; }
.authors a { color: var(--ustc-blue-deep); font-weight: 700; text-decoration-color: var(--sky); text-decoration-thickness: 2px; text-underline-offset: 4px; }
.affiliations { color: var(--muted); font-size: .86rem; }
.resource-row { display: flex; flex-wrap: wrap; justify-content: center; gap: 10px; margin: 30px 0 42px; }
.resource-link { display: inline-flex; align-items: center; gap: 8px; padding: 10px 15px; border: 1px solid var(--border); border-radius: 999px; color: var(--ustc-blue-deep); background: white; font-size: .84rem; font-weight: 700; text-decoration: none; box-shadow: 0 5px 14px rgba(0,54,96,.05); transition: .2s ease; }
.resource-link:hover { transform: translateY(-2px); border-color: var(--sky); box-shadow: 0 10px 22px rgba(0,54,96,.1); }
.resource-link.featured { color: var(--ink); background: var(--ustc-blue); border-color: var(--ustc-blue); }
.resource-icon { font-family: var(--font-mono); color: var(--orange); }
.hero-art { position: relative; min-height: clamp(300px, 47vw, 530px); overflow: hidden; display: grid; place-items: center; color: var(--ustc-blue-ink); border-radius: var(--radius-lg); background: linear-gradient(135deg, var(--blue-surface), var(--sky) 58%, var(--blue-surface)); box-shadow: var(--shadow); }
.hero-art::before { content: ""; position: absolute; width: 330px; height: 330px; border-radius: 50%; background: var(--orange); opacity: .9; filter: blur(2px); transform: translate(120%, -45%); }
.hero-grid { position: absolute; inset: 0; opacity: .2; background-image: linear-gradient(rgba(255,255,255,.4) 1px, transparent 1px), linear-gradient(90deg, rgba(255,255,255,.4) 1px, transparent 1px); background-size: 52px 52px; mask-image: linear-gradient(to right, black, transparent 75%); }
.hero-art-copy { position: relative; display: grid; gap: 8px; text-align: left; padding: 32px; }
.hero-art-copy span { font-family: var(--font-mono); letter-spacing: .16em; font-size: .8rem; color: var(--ustc-blue-deep); }
.hero-art-copy strong { max-width: 620px; font-family: var(--font-display); font-size: clamp(2.1rem, 5vw, 4.8rem); line-height: .98; }
.hero-art-copy small { color: var(--muted); }

.tldr { margin-top: 42px; padding: 30px 34px; display: grid; grid-template-columns: auto 1fr; gap: 28px; align-items: start; border-left: 6px solid var(--orange); background: var(--sky-soft); border-radius: 0 var(--radius-md) var(--radius-md) 0; }
.tldr-label { color: var(--orange-deep); font: 500 .82rem var(--font-mono); letter-spacing: .12em; }
.tldr p { margin: 0; color: var(--ustc-blue-ink); font-size: clamp(1.25rem, 2.4vw, 1.7rem); font-weight: 650; line-height: 1.42; }
.metrics { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1px; margin-top: 42px; overflow: hidden; border: 1px solid var(--border); border-radius: var(--radius-md); background: var(--border); }
.metric { padding: 28px; background: white; }
.metric strong { display: block; color: var(--ustc-blue-deep); font-family: var(--font-display); font-size: clamp(2.4rem, 5vw, 4rem); line-height: .9; }
.metric span { display: block; margin-top: 9px; color: var(--muted); font-size: .84rem; }

.content-section { padding-block: clamp(88px, 12vw, 150px); }
.section-heading { display: grid; grid-template-columns: 70px 1fr; gap: 20px; align-items: start; margin-bottom: 52px; }
.section-index { display: inline-grid; place-items: center; width: 54px; height: 54px; color: var(--ustc-blue-deep); border: 1px solid var(--sky); border-radius: 50%; font-family: var(--font-mono); font-size: .82rem; }
.prose-grid { display: grid; grid-template-columns: 1fr 1fr; gap: clamp(38px, 7vw, 92px); }
.lead { color: var(--ustc-blue-ink); font-size: clamp(1.28rem, 2.5vw, 1.72rem); font-weight: 600; line-height: 1.48; }
.lead p, .body-copy p { margin-top: 0; }
.body-copy { color: var(--muted); }
.figure-card { margin: 58px 0 0; padding: 14px; border: 1px solid var(--border); border-radius: var(--radius-md); background: white; box-shadow: 0 12px 36px rgba(0,54,96,.07); }
.figure-card img { width: 100%; border-radius: 11px; }
.figure-card figcaption { padding: 16px 8px 5px; color: var(--muted); font-size: .86rem; }
.band { background: var(--sky-soft); }
.method-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.method-card { position: relative; min-height: 290px; padding: 28px; border: 1px solid var(--border); border-radius: var(--radius-md); background: rgba(255,255,255,.78); }
.method-card::after { content: attr(data-step); position: absolute; right: 22px; top: 16px; color: var(--sky); font: 500 3.6rem var(--font-display); }
.method-card h3 { position: relative; margin: 80px 0 12px; color: var(--ustc-blue-deep); font-size: 1.2rem; }
.method-card p { position: relative; margin: 0; color: var(--muted); font-size: .92rem; }
.findings { display: grid; gap: 22px; }
.finding { display: grid; grid-template-columns: minmax(240px,.8fr) 1.5fr; overflow: hidden; border: 1px solid var(--border); border-radius: var(--radius-md); background: white; }
.finding-stat { display: grid; place-content: center; padding: 34px; color: var(--ustc-blue-deep); background: var(--blue-surface-strong); }
.finding-stat strong { color: var(--orange-deep); font-family: var(--font-display); font-size: clamp(3rem, 6vw, 5.6rem); line-height: .9; }
.finding-stat span { margin-top: 8px; font: 500 .78rem var(--font-mono); letter-spacing: .1em; text-transform: uppercase; }
.finding-copy { padding: 38px; }
.finding-copy .finding-tag { color: var(--orange-deep); font: 500 .75rem var(--font-mono); letter-spacing: .1em; text-transform: uppercase; }
.finding-copy h3 { margin: 9px 0 10px; color: var(--ustc-blue-deep); font-size: 1.4rem; }
.finding-copy p { margin: 0; color: var(--muted); }

.demo-band { color: var(--ustc-blue-ink); background: var(--blue-surface); }
.light-heading h2 { color: var(--ustc-blue-deep); }
.light-heading .kicker { color: var(--orange-deep); }
.light-heading .section-index { color: var(--ustc-blue-deep); border-color: var(--sky); }
.section-intro { max-width: var(--reading); color: var(--muted); }
.demo-tabs { display: flex; flex-wrap: wrap; gap: 8px; margin: 32px 0 20px; }
.demo-tab { padding: 9px 15px; color: var(--ustc-blue-deep); border: 1px solid var(--border); border-radius: 999px; background: rgba(255,255,255,.5); cursor: pointer; }
.demo-tab[aria-selected="true"] { color: var(--ustc-blue-deep); border-color: var(--orange); background: var(--orange); }
.demo-panel { display: grid; grid-template-columns: 1.1fr .9fr; min-height: 390px; overflow: hidden; border: 1px solid var(--border); border-radius: var(--radius-md); background: rgba(255,255,255,.65); }
.demo-visual { display: grid; place-items: center; min-height: 390px; background: linear-gradient(135deg, var(--blue-surface), var(--sky)); color: var(--ustc-blue-deep); }
.demo-visual span { max-width: 300px; font: 500 1rem var(--font-mono); text-align: center; }
.demo-copy { display: grid; align-content: center; padding: clamp(28px, 5vw, 54px); }
.demo-copy h3 { margin: 8px 0 10px; font-size: 1.55rem; }
.demo-copy p { color: var(--muted); }
.demo-copy code { color: var(--orange-deep); }

.timeline { border-top: 1px solid var(--border); }
.news-item { display: grid; grid-template-columns: 150px 1fr; gap: 28px; padding: 24px 0; border-bottom: 1px solid var(--border); }
.news-item time { color: var(--orange-deep); font: 500 .78rem var(--font-mono); text-transform: uppercase; }
.news-item p { margin: 0; }
.citation-band { background: var(--gray-soft); }
.citation-layout { display: grid; grid-template-columns: .72fr 1.28fr; gap: 52px; align-items: start; }
.citation-layout h2 { margin: 8px 0 16px; }
.citation-box { position: relative; overflow: hidden; border: 1px solid var(--border); border-radius: var(--radius-md); background: var(--blue-surface-strong); }
.citation-box pre { margin: 0; padding: 30px 28px 74px; overflow-x: auto; color: var(--ustc-blue-ink); font: 400 .78rem/1.65 var(--font-mono); white-space: pre-wrap; }
.copy-button { position: absolute; right: 14px; bottom: 14px; padding: 8px 12px; color: var(--ustc-blue-deep); border: 0; border-radius: 7px; background: var(--orange); font-weight: 700; cursor: pointer; }
.site-footer { padding: 34px 0; color: var(--muted); background: var(--blue-surface); }
.footer-layout { display: flex; justify-content: space-between; gap: 30px; font-size: .8rem; }
.footer-layout strong { display: block; color: var(--ustc-blue-deep); }
.footer-layout a { color: var(--ustc-blue-deep); }

@media (max-width: 820px) {
  .nav-toggle { display: block; }
  .nav-links { position: absolute; left: 20px; right: 20px; top: 62px; display: none; flex-direction: column; gap: 0; padding: 12px; border: 1px solid var(--border); border-radius: 12px; background: white; box-shadow: var(--shadow); }
  .nav-links[data-open="true"] { display: flex; }
  .nav-links a { padding: 10px; }
  .prose-grid, .finding, .demo-panel, .citation-layout { grid-template-columns: 1fr; }
  .method-grid { grid-template-columns: 1fr; }
  .method-card { min-height: 230px; }
  .finding-stat { min-height: 210px; }
}

@media (max-width: 620px) {
  .brand-copy { display: none; }
  .hero { padding-top: 58px; }
  .hero h1 { font-size: clamp(2.65rem, 15vw, 4.5rem); }
  .tldr { grid-template-columns: 1fr; gap: 8px; padding: 24px; }
  .metrics { grid-template-columns: 1fr; }
  .section-heading { grid-template-columns: 52px 1fr; }
  .news-item { grid-template-columns: 1fr; gap: 5px; }
  .footer-layout { flex-direction: column; }
}