/* ==========================================================================
   XU & GAN CVLAB — Academic Minimal Theme
   ========================================================================== */

:root {
  --color-bg: #ffffff;
  --color-bg-alt: #f7f8fa;
  --color-bg-dark: #0f1722;
  --color-text: #1a1a1a;
  --color-text-muted: #5a6472;
  --color-text-light: #8a94a3;
  --color-border: #e5e8ec;
  --color-border-strong: #c9cfd6;
  --color-accent: #0052a3;
  --color-accent-dark: #003c71;
  --color-accent-light: #e8f0fa;
  --color-accent-hover: #0066cc;

  --font-serif: "Source Serif Pro", "Source Han Serif SC", "Noto Serif SC", "Georgia", "Songti SC", serif;
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;

  --container: 1200px;
  --container-narrow: 960px;

  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.5rem;
  --space-6: 2rem;
  --space-7: 3rem;
  --space-8: 4rem;
  --space-9: 6rem;

  --radius-sm: 3px;
  --radius: 6px;
  --radius-lg: 10px;

  --shadow-sm: 0 1px 2px rgba(15, 23, 34, 0.05);
  --shadow: 0 2px 8px rgba(15, 23, 34, 0.08);
  --shadow-lg: 0 8px 24px rgba(15, 23, 34, 0.10);

  --transition: 0.2s ease;
}

/* ---- Reset -------------------------------------------------------------- */

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.65;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-serif);
  font-weight: 600;
  line-height: 1.25;
  margin: 0 0 var(--space-4);
  color: var(--color-text);
  letter-spacing: -0.01em;
}
h1 { font-size: clamp(2rem, 4vw, 3rem); }
h2 { font-size: clamp(1.5rem, 3vw, 2.25rem); }
h3 { font-size: 1.35rem; }
h4 { font-size: 1.1rem; }

p { margin: 0 0 var(--space-4); color: var(--color-text-muted); }
a { color: var(--color-accent); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--color-accent-hover); }
ul, ol { padding-left: 1.25rem; margin: 0 0 var(--space-4); }
li { margin-bottom: var(--space-2); color: var(--color-text-muted); }
img { max-width: 100%; display: block; }
hr { border: 0; border-top: 1px solid var(--color-border); margin: var(--space-6) 0; }
code {
  font-family: "SF Mono", Consolas, Monaco, monospace;
  font-size: 0.9em;
  padding: 0.15em 0.4em;
  background: var(--color-bg-alt);
  border-radius: var(--radius-sm);
}

/* ---- Layout ------------------------------------------------------------- */

.container { width: 100%; max-width: var(--container); margin: 0 auto; padding: 0 var(--space-5); }
.container-narrow { max-width: var(--container-narrow); margin: 0 auto; padding: 0 var(--space-5); }
.section { padding: var(--space-9) 0; }
.section-alt { background: var(--color-bg-alt); }
.section-sm { padding: var(--space-7) 0; }

.section-header { margin-bottom: var(--space-7); }
.section-header .eyebrow {
  display: inline-block;
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: var(--space-3);
}
.section-header h2 { margin-bottom: var(--space-3); }
.section-header p { max-width: 640px; font-size: 1.05rem; }

.grid { display: grid; gap: var(--space-5); }
.grid-2 { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.grid-3 { grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); }
.grid-4 { grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }

/* ---- Buttons ------------------------------------------------------------ */

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 0.75rem 1.5rem;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 500;
  border-radius: var(--radius);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
  white-space: nowrap;
}
.btn-primary { background: var(--color-accent); color: #fff; }
.btn-primary:hover { background: var(--color-accent-hover); color: #fff; transform: translateY(-1px); box-shadow: var(--shadow); }
.btn-outline { background: transparent; color: var(--color-text); border-color: var(--color-border-strong); }
.btn-outline:hover { border-color: var(--color-accent); color: var(--color-accent); }
.btn-ghost { background: transparent; color: var(--color-accent); padding: 0.5rem 0; }
.btn-ghost::after { content: "→"; transition: transform var(--transition); }
.btn-ghost:hover::after { transform: translateX(4px); }

/* ---- Header / Navigation ------------------------------------------------ */

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(180%) blur(10px);
  -webkit-backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--color-border);
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--space-5);
}
.nav-brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-family: var(--font-serif);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--color-text);
  letter-spacing: 0.02em;
}
.nav-brand:hover { color: var(--color-text); }
.nav-brand .logo-mark {
  width: 38px;
  height: 38px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--color-accent);
  color: #fff;
  font-weight: 700;
  font-family: var(--font-sans);
  font-size: 0.75rem;
  letter-spacing: 0.05em;
  border-radius: var(--radius);
}
.nav-brand .brand-text { display: flex; flex-direction: column; line-height: 1.1; }
.nav-brand .brand-text small {
  font-family: var(--font-sans);
  font-size: 0.68rem;
  font-weight: 500;
  color: var(--color-text-muted);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: var(--space-6);
  list-style: none;
  margin: 0;
  padding: 0;
}
.nav-menu li { margin: 0; }
.nav-menu a {
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--color-text);
  position: relative;
  padding: 0.25rem 0;
}
.nav-menu a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -4px;
  width: 0;
  height: 2px;
  background: var(--color-accent);
  transition: width var(--transition);
}
.nav-menu a:hover::after,
.nav-menu a.active::after { width: 100%; }
.nav-menu a.active { color: var(--color-accent); }

.nav-actions { display: flex; align-items: center; gap: var(--space-3); }
.lang-toggle {
  background: transparent;
  border: 1px solid var(--color-border-strong);
  color: var(--color-text);
  font-family: var(--font-sans);
  font-size: 0.8rem;
  font-weight: 600;
  padding: 0.35rem 0.7rem;
  border-radius: var(--radius);
  cursor: pointer;
  transition: all var(--transition);
  letter-spacing: 0.05em;
}
.lang-toggle:hover { border-color: var(--color-accent); color: var(--color-accent); }

.nav-toggle {
  display: none;
  background: transparent;
  border: 0;
  width: 40px;
  height: 40px;
  padding: 0;
  cursor: pointer;
  position: relative;
}
.nav-toggle span {
  display: block;
  position: absolute;
  left: 8px;
  right: 8px;
  height: 2px;
  background: var(--color-text);
  transition: all var(--transition);
}
.nav-toggle span:nth-child(1) { top: 13px; }
.nav-toggle span:nth-child(2) { top: 19px; }
.nav-toggle span:nth-child(3) { top: 25px; }
.nav-toggle.open span:nth-child(1) { top: 19px; transform: rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { top: 19px; transform: rotate(-45deg); }

/* ---- Hero --------------------------------------------------------------- */

.hero {
  padding: var(--space-9) 0 var(--space-8);
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute;
  top: 0; right: -200px;
  width: 600px; height: 600px;
  background: radial-gradient(circle, rgba(0, 82, 163, 0.06) 0%, transparent 70%);
  pointer-events: none;
}
.hero-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--space-5);
  position: relative;
}
.hero-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: var(--space-5);
}
.hero-eyebrow::before {
  content: ""; display: inline-block;
  width: 30px; height: 1px; background: var(--color-accent);
}
.hero h1 {
  font-size: clamp(2.25rem, 5vw, 3.75rem);
  line-height: 1.1;
  margin-bottom: var(--space-5);
  max-width: 18ch;
}
.hero h1 .accent { color: var(--color-accent); }
.hero-lead {
  font-size: clamp(1.05rem, 1.6vw, 1.2rem);
  color: var(--color-text-muted);
  max-width: 56ch;
  margin-bottom: var(--space-6);
}
.hero-affiliation {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-4);
  background: var(--color-bg-alt);
  border-left: 3px solid var(--color-accent);
  margin-bottom: var(--space-6);
  font-size: 0.95rem;
  color: var(--color-text);
}
.hero-affiliation strong { font-weight: 600; }
.hero-cta { display: flex; flex-wrap: wrap; gap: var(--space-3); }

/* ---- Page header (non-home pages) --------------------------------------- */

.page-header {
  padding: var(--space-8) 0 var(--space-7);
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg-alt);
}
.page-header .eyebrow {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: var(--space-3);
}
.page-header h1 { margin-bottom: var(--space-3); }
.page-header p { font-size: 1.05rem; max-width: 640px; margin-bottom: 0; }

/* ---- Cards -------------------------------------------------------------- */

.card {
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  transition: all var(--transition);
}
.card:hover { border-color: var(--color-border-strong); box-shadow: var(--shadow); transform: translateY(-2px); }
.card h3 { margin-bottom: var(--space-2); font-size: 1.2rem; }
.card p { margin-bottom: var(--space-3); font-size: 0.95rem; }
.card .card-tag {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: var(--space-3);
}

/* ---- Research items ----------------------------------------------------- */

.research-item {
  padding: var(--space-6);
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  transition: all var(--transition);
  display: flex;
  flex-direction: column;
}
.research-item:hover { border-color: var(--color-accent); box-shadow: var(--shadow); }
.research-item .icon {
  width: 48px; height: 48px;
  border-radius: var(--radius);
  background: var(--color-accent-light);
  color: var(--color-accent);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-serif);
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: var(--space-4);
}
.research-item h3 { font-size: 1.2rem; margin-bottom: var(--space-2); }
.research-item ul { padding-left: 1rem; margin-top: var(--space-3); margin-bottom: 0; }
.research-item ul li { font-size: 0.9rem; margin-bottom: var(--space-1); }

/* ---- Team --------------------------------------------------------------- */

.team-founders { display: grid; gap: var(--space-6); grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); }
.founder {
  display: grid;
  grid-template-columns: 140px 1fr;
  gap: var(--space-5);
  padding: var(--space-6);
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
}
.founder .avatar {
  width: 140px; height: 140px;
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, var(--color-accent) 0%, var(--color-accent-dark) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-family: var(--font-serif);
  font-size: 3rem;
  font-weight: 600;
  overflow: hidden;
}
.founder .avatar img { width: 100%; height: 100%; object-fit: cover; }
.founder h3 { margin-bottom: var(--space-1); font-size: 1.35rem; }
.founder .title {
  font-size: 0.85rem;
  color: var(--color-accent);
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  margin-bottom: var(--space-2);
}
.founder .affiliation { font-size: 0.95rem; color: var(--color-text-muted); margin-bottom: var(--space-3); }
.founder .bio { font-size: 0.92rem; margin-bottom: var(--space-3); }
.founder .links { display: flex; flex-wrap: wrap; gap: var(--space-3); font-size: 0.85rem; }
.founder .links a { color: var(--color-accent); font-weight: 500; }

.members-grid { display: grid; gap: var(--space-5); grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); }
.member {
  text-align: center;
  padding: var(--space-5) var(--space-4);
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  transition: all var(--transition);
}
.member:hover { border-color: var(--color-accent); box-shadow: var(--shadow); }
.member .avatar {
  width: 88px; height: 88px;
  border-radius: 50%;
  background: linear-gradient(135deg, #dfe5ec, #b8c2cf);
  color: #fff;
  margin: 0 auto var(--space-3);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-serif);
  font-size: 1.8rem;
  font-weight: 600;
  overflow: hidden;
}
.member .avatar img { width: 100%; height: 100%; object-fit: cover; }
.member .name { font-weight: 600; margin-bottom: var(--space-1); color: var(--color-text); }
.member .role { font-size: 0.82rem; color: var(--color-text-muted); }

.team-group-title {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin: var(--space-7) 0 var(--space-5);
  font-family: var(--font-serif);
  font-size: 1.35rem;
  font-weight: 600;
}
.team-group-title::after {
  content: ""; flex: 1; height: 1px; background: var(--color-border);
}

/* ---- Publications ------------------------------------------------------- */

.pub-filter {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-bottom: var(--space-6);
  padding-bottom: var(--space-5);
  border-bottom: 1px solid var(--color-border);
}
.pub-filter button {
  background: transparent;
  border: 1px solid var(--color-border);
  color: var(--color-text-muted);
  font-family: var(--font-sans);
  font-size: 0.85rem;
  font-weight: 500;
  padding: 0.4rem 0.9rem;
  border-radius: 999px;
  cursor: pointer;
  transition: all var(--transition);
}
.pub-filter button:hover { color: var(--color-accent); border-color: var(--color-accent); }
.pub-filter button.active { background: var(--color-accent); color: #fff; border-color: var(--color-accent); }

.pub-list { list-style: none; padding: 0; margin: 0; }
.pub-item {
  display: grid;
  grid-template-columns: 90px 1fr;
  gap: var(--space-5);
  padding: var(--space-5) 0;
  border-bottom: 1px solid var(--color-border);
  margin: 0;
}
.pub-item:last-child { border-bottom: 0; }
.pub-item .pub-year {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--color-accent);
  line-height: 1;
}
.pub-item .pub-venue {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--color-accent);
  background: var(--color-accent-light);
  padding: 0.2rem 0.55rem;
  border-radius: var(--radius-sm);
  margin-bottom: var(--space-2);
}
.pub-item .pub-title {
  font-family: var(--font-serif);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--space-2);
  line-height: 1.4;
}
.pub-item .pub-authors { font-size: 0.92rem; color: var(--color-text-muted); margin-bottom: var(--space-2); }
.pub-item .pub-authors em { color: var(--color-text); font-style: normal; font-weight: 600; }
.pub-item .pub-links { display: flex; flex-wrap: wrap; gap: var(--space-3); font-size: 0.85rem; }
.pub-item .pub-links a { font-weight: 500; }

/* ---- News --------------------------------------------------------------- */

.news-list { list-style: none; padding: 0; margin: 0; }
.news-item {
  display: grid;
  grid-template-columns: 120px 1fr;
  gap: var(--space-5);
  padding: var(--space-5) 0;
  border-bottom: 1px solid var(--color-border);
  margin: 0;
  align-items: start;
}
.news-item:last-child { border-bottom: 0; }
.news-item .news-date {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  font-variant-numeric: tabular-nums;
}
.news-item .news-title {
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: 1.05rem;
  margin-bottom: var(--space-1);
  color: var(--color-text);
}
.news-item .news-body { font-size: 0.92rem; margin-bottom: 0; }

.news-tag {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: #fff;
  background: var(--color-accent);
  padding: 0.15rem 0.5rem;
  border-radius: var(--radius-sm);
  margin-right: var(--space-2);
  vertical-align: 2px;
}
.news-tag.award { background: #b8860b; }
.news-tag.paper { background: #0052a3; }
.news-tag.event { background: #486b7a; }

/* ---- Projects ----------------------------------------------------------- */

.project-grid { display: grid; gap: var(--space-5); grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); }
.project-card {
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: all var(--transition);
}
.project-card:hover { border-color: var(--color-accent); box-shadow: var(--shadow-lg); transform: translateY(-3px); }
.project-card .project-cover {
  height: 180px;
  background: linear-gradient(135deg, var(--color-accent-light) 0%, #d4e4f5 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-accent-dark);
  font-family: var(--font-serif);
  font-size: 2rem;
  font-weight: 700;
  position: relative;
  overflow: hidden;
}
.project-card .project-cover::before {
  content: "";
  position: absolute; inset: 0;
  background-image:
    linear-gradient(to right, rgba(0,82,163,0.08) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(0,82,163,0.08) 1px, transparent 1px);
  background-size: 20px 20px;
  pointer-events: none;
}
.project-card .project-body { padding: var(--space-5); flex: 1; display: flex; flex-direction: column; }
.project-card .project-tag {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--color-accent);
  margin-bottom: var(--space-2);
}
.project-card h3 { font-size: 1.15rem; margin-bottom: var(--space-2); }
.project-card p { font-size: 0.9rem; margin-bottom: var(--space-4); flex: 1; }
.project-card .project-meta { display: flex; gap: var(--space-4); font-size: 0.8rem; color: var(--color-text-muted); }

.award-list { list-style: none; padding: 0; margin: 0; }
.award-item {
  display: grid;
  grid-template-columns: 50px 1fr auto;
  gap: var(--space-4);
  padding: var(--space-4) 0;
  border-bottom: 1px solid var(--color-border);
  margin: 0;
  align-items: center;
}
.award-item:last-child { border-bottom: 0; }
.award-item .award-icon {
  width: 44px; height: 44px;
  border-radius: var(--radius);
  background: #fdf5dc;
  color: #b8860b;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.35rem;
}
.award-item .award-title { font-weight: 600; color: var(--color-text); margin-bottom: var(--space-1); }
.award-item .award-meta { font-size: 0.85rem; color: var(--color-text-muted); }
.award-item .award-year {
  font-family: var(--font-serif);
  font-weight: 600;
  color: var(--color-accent);
  white-space: nowrap;
}

/* ---- Contact ------------------------------------------------------------ */

.contact-grid { display: grid; gap: var(--space-6); grid-template-columns: 1fr 1fr; }
.contact-info h3 { font-size: 1.1rem; margin-bottom: var(--space-3); }
.contact-info .info-row {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  padding: var(--space-4) 0;
  border-bottom: 1px solid var(--color-border);
}
.contact-info .info-row:last-child { border-bottom: 0; }
.contact-info .info-label {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  min-width: 90px;
  padding-top: 3px;
}
.contact-info .info-value { flex: 1; color: var(--color-text); font-size: 0.95rem; }
.contact-info .info-value a { font-weight: 500; }

.contact-form {
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
}
.form-row { margin-bottom: var(--space-4); }
.form-row label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: var(--space-2);
  color: var(--color-text);
}
.form-row input,
.form-row textarea {
  width: 100%;
  padding: 0.7rem 0.9rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font-family: inherit;
  font-size: 0.95rem;
  color: var(--color-text);
  background: #fff;
  transition: border-color var(--transition), box-shadow var(--transition);
}
.form-row input:focus,
.form-row textarea:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(0, 82, 163, 0.12);
}
.form-row textarea { min-height: 120px; resize: vertical; }

/* ---- Stats strip -------------------------------------------------------- */

.stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: var(--space-5);
  padding: var(--space-6) 0;
}
.stat { text-align: left; padding: 0 var(--space-3); border-left: 3px solid var(--color-accent); }
.stat .stat-number {
  font-family: var(--font-serif);
  font-size: clamp(2rem, 4vw, 2.75rem);
  font-weight: 700;
  color: var(--color-text);
  line-height: 1;
  margin-bottom: var(--space-2);
}
.stat .stat-label {
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-muted);
}

/* ---- Footer ------------------------------------------------------------- */

.site-footer {
  background: var(--color-bg-dark);
  color: #b8c2cf;
  padding: var(--space-8) 0 var(--space-5);
  margin-top: var(--space-9);
}
.site-footer a { color: #dfe5ec; }
.site-footer a:hover { color: #fff; }
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-6);
  margin-bottom: var(--space-7);
}
.footer-grid h4 {
  color: #fff;
  font-family: var(--font-sans);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: var(--space-4);
}
.footer-grid ul { list-style: none; padding: 0; margin: 0; }
.footer-grid li { margin-bottom: var(--space-2); font-size: 0.9rem; color: #b8c2cf; }
.footer-brand { font-family: var(--font-serif); font-size: 1.3rem; color: #fff; margin-bottom: var(--space-3); font-weight: 700; }
.footer-brand-desc { font-size: 0.9rem; max-width: 340px; line-height: 1.6; }
.footer-bottom {
  padding-top: var(--space-5);
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.82rem;
  color: #8a94a3;
  flex-wrap: wrap;
  gap: var(--space-3);
}

/* ---- Language toggling -------------------------------------------------- */

html[lang="zh"] [data-en]:not([data-zh]) { display: none; }
html[lang="en"] [data-zh]:not([data-en]) { display: none; }
[data-zh][data-en] .lang-zh,
[data-zh][data-en] .lang-en { display: none; }
html[lang="zh"] [data-zh][data-en] .lang-zh,
html[lang="en"] [data-zh][data-en] .lang-en { display: inline; }

/* ---- Utility ------------------------------------------------------------ */

.text-center { text-align: center; }
.mt-0 { margin-top: 0; }
.mb-0 { margin-bottom: 0; }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }
.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0, 0, 0, 0); border: 0;
}

/* ---- Responsive --------------------------------------------------------- */

@media (max-width: 960px) {
  .contact-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: var(--space-5); }
  .footer-grid > :first-child { grid-column: 1 / -1; }
}

@media (max-width: 768px) {
  .section { padding: var(--space-8) 0; }
  .hero { padding: var(--space-7) 0 var(--space-7); }

  .nav { height: 64px; }
  .nav-toggle { display: block; }
  .nav-menu {
    position: fixed;
    top: 64px;
    left: 0;
    right: 0;
    bottom: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: var(--space-5);
    background: #fff;
    border-top: 1px solid var(--color-border);
    transform: translateX(100%);
    transition: transform 0.3s ease;
    overflow-y: auto;
  }
  .nav-menu.open { transform: translateX(0); }
  .nav-menu li { border-bottom: 1px solid var(--color-border); }
  .nav-menu a {
    display: block;
    padding: var(--space-4) 0;
    font-size: 1rem;
  }
  .nav-menu a::after { display: none; }

  .nav-brand .brand-text small { display: none; }

  .founder {
    grid-template-columns: 1fr;
    text-align: center;
  }
  .founder .avatar { margin: 0 auto; width: 120px; height: 120px; }
  .founder .links { justify-content: center; }

  .pub-item,
  .news-item {
    grid-template-columns: 1fr;
    gap: var(--space-2);
  }
  .pub-item .pub-year { font-size: 1.1rem; }
  .news-item .news-date { font-size: 0.8rem; }

  .award-item { grid-template-columns: 44px 1fr; }
  .award-item .award-year { grid-column: 2; font-size: 0.85rem; margin-top: 2px; }

  .footer-grid { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; text-align: center; }
}

@media (max-width: 480px) {
  :root { --space-9: 4rem; --space-8: 3rem; }
  .members-grid { grid-template-columns: repeat(2, 1fr); }
  .members-grid .member { padding: var(--space-4) var(--space-3); }
  .members-grid .member .avatar { width: 70px; height: 70px; font-size: 1.4rem; }
  .hero-cta .btn { width: 100%; justify-content: center; }
}

/* ---- Reduced motion ----------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}