:root {
  --brand: #1f4f96;
  --brand-strong: #163d78;
  --accent: #89c6ff;
  --ink: #111827;
  --muted: #6b7280;
  --surface: #ffffff;
  --surface-soft: #f5f5f7;
  --line: rgba(17, 24, 39, 0.08);
  --shadow: 0 12px 36px rgba(15, 23, 42, 0.05);
  --max-width: 1320px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  font-family: "Hiragino Sans GB", "Noto Sans SC", "PingFang SC", "Source Sans 3",
    "Microsoft YaHei", sans-serif;
  background:
    radial-gradient(circle at top left, rgba(137, 198, 255, 0.1), transparent 20%),
    linear-gradient(180deg, #fbfbfd 0%, #f5f5f7 100%);
}

a {
  color: inherit;
  text-decoration: none;
}

img {
  display: block;
  width: 100%;
}

.lang {
  display: none;
}

body[data-lang="zh"] .lang.zh,
body[data-lang="en"] .lang.en {
  display: inline;
}

body[data-lang="zh"] p.lang.zh,
body[data-lang="en"] p.lang.en {
  display: block;
}

.site {
  min-height: 100vh;
}

.top-line {
  height: 2px;
  background: linear-gradient(90deg, rgba(137, 198, 255, 0.85), rgba(137, 198, 255, 0.4));
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: rgba(251, 251, 253, 0.82);
  box-shadow: 0 1px 0 rgba(15, 23, 42, 0.05);
  backdrop-filter: saturate(180%) blur(22px);
}

.header-inner,
.main-nav,
.page,
.site-footer {
  width: min(var(--max-width), calc(100% - 48px));
  margin: 0 auto;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 20px 0 12px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 18px;
  color: var(--brand);
}

.brand-mark {
  width: 54px;
  height: 54px;
  border-radius: 16px;
  background:
    linear-gradient(135deg, rgba(137, 198, 255, 0.18), rgba(31, 79, 150, 0.1)),
    var(--surface);
  box-shadow: inset 0 0 0 1px rgba(17, 24, 39, 0.06);
}

.brand-copy p,
.brand-copy h1 {
  margin: 0;
}

.brand-copy .department {
  color: var(--brand);
  font-size: 0.94rem;
  font-weight: 700;
}

.brand-copy h1 {
  margin-top: 4px;
  font-size: clamp(1.92rem, 2.8vw, 2.85rem);
  line-height: 1.01;
  letter-spacing: -0.03em;
  font-weight: 700;
}

.brand-copy .subtitle {
  margin-top: 6px;
  color: var(--muted);
  font-size: 0.98rem;
}

.header-tools {
  display: flex;
  align-items: center;
  gap: 18px;
}

.language-wrap {
  display: inline-flex;
  align-items: center;
  gap: 10px;
}

.language-label {
  color: var(--muted);
  font-size: 0.94rem;
  font-weight: 600;
}

.language-menu {
  position: relative;
}

.language-trigger,
.language-option,
.header-link,
.menu-button {
  min-height: 38px;
  border: 0;
  border-radius: 16px;
  background: transparent;
  color: var(--muted);
  font: inherit;
  font-size: 0.95rem;
  cursor: pointer;
}

.language-trigger {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-width: 146px;
  padding: 0 14px;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.82);
  list-style: none;
}

.language-trigger::-webkit-details-marker {
  display: none;
}

.language-trigger::after {
  margin-left: auto;
  color: var(--brand);
  content: "▾";
}

.language-menu[open] .language-trigger::after {
  content: "▴";
}

.language-trigger-short,
.language-option-short {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 999px;
  color: var(--brand);
  font-size: 0.84rem;
  font-weight: 700;
  background: rgba(36, 89, 166, 0.1);
}

.language-trigger-label {
  color: var(--ink);
  font-weight: 700;
}

.language-dropdown {
  position: absolute;
  right: 0;
  top: calc(100% + 10px);
  z-index: 30;
  display: grid;
  gap: 8px;
  min-width: 220px;
  padding: 10px;
  border: 1px solid var(--line);
  border-radius: 22px;
  background: rgba(255, 255, 255, 0.98);
  box-shadow: 0 20px 40px rgba(15, 23, 42, 0.14);
}

.language-option {
  display: inline-flex;
  align-items: center;
  justify-content: flex-start;
  gap: 10px;
  width: 100%;
  padding: 0 12px;
  color: var(--ink);
  background: rgba(36, 89, 166, 0.04);
}

.language-option.is-active {
  color: white;
  background: var(--brand);
}

.language-option.is-active .language-option-short {
  color: white;
  background: rgba(255, 255, 255, 0.18);
}

.header-link {
  display: inline-flex;
  align-items: center;
  padding: 0;
  font-weight: 600;
}

.menu-button {
  display: none;
  width: 42px;
  min-height: 42px;
  border-radius: 14px;
  border: 1px solid var(--line);
}

.menu-button span {
  display: block;
  width: 18px;
  height: 2px;
  margin: 4px auto;
  border-radius: 999px;
  background: var(--ink);
}

.main-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: clamp(20px, 3.2vw, 48px);
}

.main-nav a {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 16px 0 18px;
  min-width: 74px;
  color: #4b5563;
  font-size: clamp(0.98rem, 1.2vw, 1.08rem);
  font-weight: 700;
}

.main-nav a::after {
  position: absolute;
  left: 10px;
  right: 10px;
  bottom: 0;
  height: 4px;
  border-radius: 999px;
  background: transparent;
  content: "";
}

.main-nav a.is-active::after,
.main-nav a:hover::after {
  background: var(--accent);
}

.main-nav.is-open {
  display: flex;
}

.page {
  padding: 0 0 96px;
}

.hero {
  position: relative;
  overflow: hidden;
  border-radius: 0 0 32px 32px;
  min-height: 640px;
  background: #d9e1ea;
}

.hero-slides,
.hero-slide {
  position: absolute;
  inset: 0;
}

.hero-slide {
  opacity: 0;
  background-position: center center;
  background-size: cover;
  background-repeat: no-repeat;
  transition: opacity 800ms ease;
}

.hero-slide::after {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(180deg, rgba(15, 23, 42, 0.08), rgba(15, 23, 42, 0.18)),
    linear-gradient(0deg, rgba(255, 255, 255, 0.04), rgba(255, 255, 255, 0.04));
  content: "";
}

.hero-slide.is-active {
  opacity: 1;
}

.hero-copy {
  position: absolute;
  left: 50%;
  top: 112px;
  z-index: 2;
  width: min(1080px, calc(100% - 120px));
  transform: translateX(-50%);
}

.hero-copy p,
.hero-copy h2 {
  margin: 0;
  color: white;
}

.hero-copy .eyebrow {
  font-size: 0.84rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  opacity: 0.86;
}

.hero-copy h2 {
  max-width: 720px;
  margin-top: 18px;
  font-size: clamp(2.8rem, 5.6vw, 4.7rem);
  line-height: 0.96;
  letter-spacing: -0.04em;
  font-weight: 700;
}

.hero-copy .lead {
  max-width: 560px;
  margin-top: 16px;
  color: rgba(255, 255, 255, 0.82);
  font-size: 1rem;
  line-height: 1.8;
}

.hero-controls {
  position: absolute;
  right: 34px;
  bottom: 28px;
  z-index: 3;
  display: flex;
  align-items: center;
  gap: 8px;
}

.hero-arrow {
  width: 38px;
  height: 38px;
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 999px;
  color: white;
  font-size: 1.3rem;
  background: rgba(15, 23, 42, 0.26);
  backdrop-filter: blur(10px);
  cursor: pointer;
}

.hero-dots {
  display: flex;
  gap: 10px;
}

.hero-dot {
  width: 7px;
  height: 7px;
  padding: 0;
  border: 0;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.46);
  cursor: pointer;
}

.hero-dot.is-active {
  width: 22px;
  background: white;
}

.section {
  margin-top: 64px;
}

.section-head {
  margin-bottom: 24px;
}

.section-head .mark {
  display: inline-block;
  width: 42px;
  height: 2px;
  border-radius: 999px;
  background: rgba(31, 79, 150, 0.5);
}

.section-head h2,
.section-head p {
  margin: 0;
}

.section-head h2 {
  margin-top: 16px;
  font-size: clamp(2rem, 2.8vw, 2.7rem);
  line-height: 1.04;
  letter-spacing: -0.03em;
  font-weight: 700;
}

.section-head p {
  margin-top: 12px;
  max-width: 680px;
  color: var(--muted);
  font-size: 1rem;
  line-height: 1.8;
}

.panel,
.news-list article,
.research-grid article,
.member-card,
.group-card,
.paper-card,
.gallery-card,
.contact-card,
.archive-year {
  border: 1px solid var(--line);
  border-radius: 26px;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.home-overview-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(300px, 0.85fr);
  gap: 18px;
  align-items: stretch;
}

.intro-panel {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 20px;
  align-items: start;
  padding: 34px 36px;
}

.intro-panel h3,
.panel-title {
  margin: 0 0 10px;
  font-size: 1.22rem;
  line-height: 1.25;
  letter-spacing: -0.02em;
}

.intro-panel p,
.news-list p,
.research-grid p,
.member-card p,
.group-card p,
.paper-card p,
.contact-card p,
.archive-year p {
  margin: 0;
  color: var(--muted);
  line-height: 1.78;
}

.ghost-link {
  display: inline-flex;
  align-items: center;
  padding: 0 18px;
  min-height: 44px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--ink);
  font-weight: 700;
  background: rgba(255, 255, 255, 0.72);
}

.quick-panel {
  padding: 26px 24px 18px;
  background: rgba(255, 255, 255, 0.72);
}

.quick-link-list {
  display: grid;
  gap: 10px;
}

.quick-link-item {
  display: grid;
  grid-template-columns: 48px minmax(0, 1fr);
  gap: 14px;
  padding: 14px 4px;
  border-radius: 0;
  border-bottom: 1px solid var(--line);
  transition: opacity 180ms ease, transform 180ms ease;
}

.quick-link-item:last-child {
  border-bottom: 0;
}

.quick-link-item:hover {
  opacity: 0.86;
  transform: translateX(2px);
}

.quick-link-item .index {
  color: rgba(36, 89, 166, 0.58);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  padding-top: 2px;
}

.quick-link-item strong {
  display: block;
  color: var(--ink);
  font-size: 1rem;
}

.quick-link-item p {
  margin: 4px 0 0;
  color: var(--muted);
  line-height: 1.65;
}

.news-shell {
  display: grid;
  grid-template-columns: 1.3fr 0.7fr;
  gap: 20px;
}

.news-list {
  display: grid;
  gap: 14px;
}

.news-list article {
  padding: 22px 24px;
}

.news-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 10px;
  font-size: 0.95rem;
  color: var(--muted);
}

.news-tag {
  padding: 5px 10px;
  border-radius: 999px;
  color: white;
  font-weight: 700;
  background: #eb7ba4;
}

.news-list h3 {
  margin: 0 0 8px;
  font-size: 1.08rem;
  line-height: 1.4;
}

.stats-panel {
  padding: 22px;
}

.stat-grid {
  display: grid;
  gap: 12px;
}

.stat-item {
  padding: 16px 18px;
  border-radius: 18px;
  background: var(--surface-soft);
}

.stat-item strong {
  display: block;
  font-size: 1.8rem;
  line-height: 1;
}

.stat-item span {
  display: block;
  margin-top: 8px;
  color: var(--muted);
}

.subhero {
  padding: 88px 0 36px;
}

.subhero-card {
  overflow: hidden;
  border-radius: 28px;
  background:
    linear-gradient(180deg, rgba(15, 23, 42, 0.36), rgba(15, 23, 42, 0.3)),
    linear-gradient(135deg, rgba(137, 198, 255, 0.12), rgba(31, 79, 150, 0.14));
  box-shadow: var(--shadow);
}

.subhero-inner {
  padding: 48px 52px;
}

.subhero .eyebrow {
  color: rgba(255, 255, 255, 0.84);
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.subhero h2 {
  margin: 12px 0 0;
  color: white;
  font-size: clamp(2.2rem, 4vw, 3.6rem);
  line-height: 1;
  letter-spacing: -0.04em;
}

.subhero p {
  max-width: 760px;
  margin: 16px 0 0;
  color: rgba(255, 255, 255, 0.84);
  line-height: 1.8;
}

.local-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 18px;
}

.local-nav a {
  display: inline-flex;
  align-items: center;
  padding: 0 16px;
  min-height: 40px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.1);
  color: white;
  font-weight: 700;
}

.research-grid,
.member-layout,
.publication-layout,
.lab-layout,
.gallery-grid,
.access-layout {
  display: grid;
  gap: 18px;
}

.research-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.research-grid article,
.member-card,
.group-card,
.paper-card,
.contact-card,
.archive-year {
  padding: 26px;
}

.research-grid h3,
.member-card h3,
.group-card h3,
.paper-card h3,
.contact-card h3,
.archive-year h3 {
  margin: 0 0 10px;
  font-size: 1.2rem;
  line-height: 1.3;
}

.member-layout {
  grid-template-columns: 1fr 1fr;
}

.member-card figure {
  margin: 0 0 16px;
  overflow: hidden;
  border-radius: 22px;
}

.member-card img {
  aspect-ratio: 4 / 4.6;
  object-fit: cover;
  object-position: center 14%;
}

.meta-list {
  display: grid;
  gap: 12px;
  margin-top: 16px;
}

.meta-list div {
  padding: 14px 16px;
  border-radius: 18px;
  background: var(--surface-soft);
}

.meta-list strong {
  display: block;
  margin-bottom: 4px;
}

.group-card ul,
.source-list,
.archive-list {
  margin: 0;
  padding-left: 18px;
}

.group-card li,
.source-list li,
.archive-list li {
  color: var(--muted);
  line-height: 1.8;
}

.publication-layout {
  grid-template-columns: 300px minmax(0, 1fr);
  align-items: start;
}

.paper-list {
  display: grid;
  gap: 14px;
}

.paper-card {
  display: grid;
  grid-template-columns: 108px 1fr;
  overflow: hidden;
  padding: 0;
}

.paper-year {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
  color: var(--brand-strong);
  font-size: 1.06rem;
  font-weight: 800;
  background: var(--surface-soft);
}

.paper-card .body {
  padding: 22px 24px;
}

.paper-card .body a {
  color: var(--brand-strong);
  font-weight: 700;
}

.lab-layout {
  grid-template-columns: 1fr 1fr;
}

.gallery-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.gallery-card {
  overflow: hidden;
}

.gallery-card img {
  aspect-ratio: 4 / 3;
  object-fit: cover;
}

.gallery-card figcaption {
  padding: 16px 18px;
  color: var(--muted);
  line-height: 1.7;
}

.quote-card {
  padding: 24px;
}

.quote-card blockquote {
  margin: 0;
  padding: 18px 18px 18px 20px;
  border-left: 3px solid rgba(31, 79, 150, 0.6);
  border-radius: 0 18px 18px 0;
  background: var(--surface-soft);
  color: #334155;
  line-height: 1.8;
}

.archive-wrap {
  display: grid;
  gap: 18px;
}

.archive-year .head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 14px;
}

.archive-list {
  display: grid;
  gap: 14px;
  padding-left: 0;
  list-style: none;
}

.archive-list li {
  padding-top: 14px;
  border-top: 1px solid var(--line);
}

.archive-list li:first-child {
  padding-top: 0;
  border-top: 0;
}

.archive-list h4,
.archive-list p {
  margin: 0;
}

.archive-list h4 {
  color: var(--ink);
  font-size: 1.06rem;
}

.access-layout {
  grid-template-columns: 1fr 1fr;
}

.source-list a {
  color: var(--brand-strong);
}

.site-footer {
  margin-top: 78px;
  padding: 36px 0 60px;
}

.footer-panel {
  padding: 28px 30px;
}

.footer-panel > h3,
.footer-panel > p {
  margin: 0;
}

.footer-panel > h3 {
  color: var(--brand);
  font-size: 1.4rem;
}

.footer-panel > p {
  margin-top: 10px;
  color: var(--muted);
  line-height: 1.8;
}

.footer-sitemap {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 18px;
  margin-top: 22px;
  padding-top: 22px;
  border-top: 1px solid var(--line);
}

.footer-sitemap h4,
.footer-sitemap ul {
  margin: 0;
}

.footer-sitemap h4 {
  font-size: 1rem;
}

.footer-sitemap ul {
  padding-left: 18px;
  margin-top: 8px;
}

.footer-sitemap li {
  color: var(--muted);
  line-height: 1.8;
}

.copyright {
  margin-top: 20px;
  color: var(--muted);
  font-size: 0.94rem;
}

@media (max-width: 1120px) {
  .header-inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .main-nav {
    flex-wrap: wrap;
    justify-content: flex-start;
  }

  .hero-copy {
    width: min(100%, calc(100% - 64px));
  }

  .research-grid,
  .member-layout,
  .publication-layout,
  .lab-layout,
  .gallery-grid,
  .access-layout,
  .news-shell,
  .footer-sitemap,
  .home-overview-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .hero {
    min-height: 580px;
  }

  .hero-controls {
    bottom: 28px;
  }
}

@media (max-width: 760px) {
  .header-inner,
  .main-nav,
  .page,
  .site-footer {
    width: min(var(--max-width), calc(100% - 24px));
  }

  .header-tools {
    width: 100%;
    justify-content: space-between;
    gap: 10px;
  }

  .language-wrap {
    flex-direction: column;
    align-items: flex-start;
  }

  .language-label,
  .header-link {
    font-size: 0.88rem;
  }

  .language-dropdown {
    left: 0;
    right: auto;
    min-width: 200px;
  }

  .menu-button {
    display: inline-flex;
    flex-direction: column;
    justify-content: center;
  }

  .main-nav {
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 10px 0 14px;
  }

  .main-nav a {
    justify-content: flex-start;
    padding: 14px 2px;
    border-bottom: 1px solid var(--line);
  }

  .main-nav a:last-child {
    border-bottom: 0;
  }

  .main-nav a::after {
    left: 0;
    right: auto;
    bottom: 8px;
    width: 28px;
  }

  .hero {
    min-height: 390px;
    border-radius: 0 0 22px 22px;
  }

  .hero-copy {
    top: 52px;
    width: calc(100% - 32px);
  }

  .hero-copy h2 {
    max-width: 100%;
    font-size: 2rem;
  }

  .hero-copy .lead {
    font-size: 1rem;
    line-height: 1.68;
  }

  .hero-controls {
    right: 14px;
    bottom: 14px;
  }

  .hero-arrow {
    width: 36px;
    height: 36px;
    font-size: 1.28rem;
  }

  .research-grid,
  .member-layout,
  .publication-layout,
  .lab-layout,
  .gallery-grid,
  .access-layout,
  .news-shell,
  .footer-sitemap,
  .home-overview-grid {
    grid-template-columns: 1fr;
  }

  .section {
    margin-top: 42px;
  }

  .section-head h2 {
    font-size: 1.74rem;
  }

  .panel,
  .news-list article,
  .research-grid article,
  .member-card,
  .group-card,
  .paper-card,
  .gallery-card,
  .contact-card,
  .archive-year {
    border-radius: 20px;
  }

  .intro-panel,
  .research-grid article,
  .member-card,
  .group-card,
  .quote-card,
  .contact-card,
  .archive-year {
    padding: 22px 18px;
  }

  .intro-panel {
    grid-template-columns: 1fr;
  }

  .quick-panel {
    padding: 22px 18px 14px;
  }

  .paper-card {
    grid-template-columns: 1fr;
  }

  .paper-year {
    justify-content: flex-start;
    padding: 14px 18px;
  }

  .paper-card .body {
    padding: 18px;
  }

  .subhero {
    padding-top: 34px;
  }

  .subhero-inner {
    padding: 26px 22px;
  }

  .member-card img {
    aspect-ratio: 4 / 3.8;
  }
}