/* Dr. Jacob Chengwei Feng — v4
   v3 structure (NVIDIA-shaped) in v1 palette (ivory + jade + bronze)
   Type: Libre Caslon Display + Lora
*/

:root {
  --paper: #f4ede0;
  --paper-card: #fbf6ec;
  --paper-card-hover: #fffaf0;
  --paper-deep: #e8dec3;
  --paper-elev: #ece4d2;

  --ink: #1a1818;
  --ink-soft: #3a3633;
  --ink-mute: #6b645c;
  --ink-faint: #a39780;

  --jade: #3d6b5c;
  --jade-bright: #4f8270;
  --jade-deep: #284b40;
  --jade-soft: #6a9082;
  --jade-glow: rgba(61, 107, 92, 0.12);

  --bronze: #8a6a3a;
  --bronze-bright: #a48043;
  --bronze-deep: #5e4724;
  --bronze-soft: #b89762;

  --rule: #d6caad;
  --rule-soft: #e6ddc7;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; background: var(--paper); }
body {
  margin: 0;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  font-size: 17px;
  line-height: 1.6;
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, .display {
  font-family: 'EB Garamond', 'Times New Roman', serif;
  font-weight: 500;
  color: var(--ink);
  letter-spacing: -0.005em;
}

a {
  color: var(--jade);
  text-decoration: none;
  transition: color .15s;
}
a:hover { color: var(--jade-deep); }

p { margin: 0 0 1em; }

.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 32px;
}

/* ─── header / nav (jade) ─── */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: linear-gradient(180deg, #4f8270 0%, #3d6b5c 100%);
  border-bottom: 1px solid var(--jade-deep);
  box-shadow: 0 2px 12px rgba(40, 75, 64, 0.18);
}
.nav-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 0;
}
.nav-brand {
  font-family: 'EB Garamond', serif;
  font-size: 20px;
  font-weight: 400;
  letter-spacing: -0.01em;
  color: var(--paper);
}
.nav-brand .accent { color: var(--paper); font-style: italic; }
.nav-brand:hover { color: var(--paper-card); }
.nav-links {
  display: flex;
  gap: 32px;
  font-size: 14px;
  font-weight: 500;
  font-family: 'Inter', sans-serif;
}
.nav-links a {
  color: var(--paper);
  letter-spacing: 0.01em;
  opacity: 0.88;
}
.nav-links a:hover { color: var(--paper-card); opacity: 1; }
.nav-toggle {
  display: none;
  background: none;
  border: 0;
  font-size: 22px;
  color: var(--paper);
  cursor: pointer;
  padding: 4px 8px;
}
@media (max-width: 860px) {
  .nav-links {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: linear-gradient(180deg, #4f8270 0%, #3d6b5c 100%);
    border-bottom: 1px solid var(--jade-deep);
    flex-direction: column;
    gap: 0;
    padding: 12px 0;
    display: none;
  }
  .nav-links.open { display: flex; }
  .nav-links a { padding: 12px 32px; color: var(--paper); }
  .nav-toggle { display: inline-block; }
}

/* ─── eyebrow ─── */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--bronze);
  margin-bottom: 20px;
  font-family: 'Inter', sans-serif;
}
.eyebrow::before {
  content: "";
  width: 10px;
  height: 1px;
  background: var(--bronze);
}

/* ─── buttons ─── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 26px;
  font-family: 'Inter', sans-serif;
  font-size: 14.5px;
  font-weight: 500;
  letter-spacing: 0.04em;
  cursor: pointer;
  transition: background .15s, color .15s, transform .15s, border-color .15s;
  border-radius: 999px;
  border: 1px solid var(--jade);
  background: var(--jade);
  color: var(--paper);
}
.btn:hover { background: var(--jade-deep); border-color: var(--jade-deep); color: var(--paper); transform: translateY(-1px); }
.btn-secondary {
  background: transparent;
  color: var(--ink);
  border-color: var(--rule);
}
.btn-secondary:hover { background: transparent; border-color: var(--jade); color: var(--jade-deep); transform: translateY(-1px); }
.btn-arrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 14px;
  color: var(--jade);
  font-weight: 500;
  font-family: 'Inter', sans-serif;
}
.btn-arrow::after { content: "→"; transition: transform .15s; }
.btn-arrow:hover::after { transform: translateX(3px); }

/* ─── hero (About-as-hero) ─── */
.hero {
  padding: 88px 0 96px;
  position: relative;
  overflow: hidden;
  border-bottom: 1px solid var(--rule);
  background:
    radial-gradient(circle at 82% 30%, rgba(61, 107, 92, 0.08), transparent 50%),
    radial-gradient(circle at 12% 80%, rgba(138, 106, 58, 0.05), transparent 45%);
}
.hero-grid {
  display: grid;
  grid-template-columns: 1.25fr 1fr;
  gap: 72px;
  align-items: center;
}
.hero h1 {
  font-size: clamp(40px, 6.4vw, 88px);
  line-height: 1.02;
  margin: 0 0 20px;
  font-weight: 500;
  letter-spacing: -0.018em;
}
.hero h1 .accent { color: var(--jade); font-style: italic; }
.hero-tag {
  font-size: clamp(18px, 1.6vw, 22px);
  line-height: 1.5;
  color: var(--ink-soft);
  margin: 0 0 28px;
  max-width: 580px;
  font-family: 'EB Garamond', serif;
  font-style: italic;
  font-weight: 400;
}
.hero-bio {
  max-width: 600px;
  margin-bottom: 28px;
}
.hero-bio p {
  font-size: 16px;
  line-height: 1.65;
  color: var(--ink-soft);
  margin: 0 0 1em;
}
.hero-bio p em { color: var(--ink); font-style: italic; }
.role-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0 0 32px;
  max-width: 600px;
}
.role-chips span {
  display: inline-block;
  padding: 6px 14px;
  font-size: 12px;
  letter-spacing: 0.02em;
  color: var(--ink-soft);
  background: var(--paper-card);
  border: 1px solid var(--rule);
  border-radius: 999px;
  white-space: nowrap;
}
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; }

.hero-feature { position: relative; display: flex; align-items: center; justify-content: center; }
.hero-portrait-big { position: relative; width: 360px; }
.hero-portrait-big .frame {
  width: 360px;
  height: 360px;
  overflow: hidden;
  background: var(--paper-deep);
  border: 1px solid var(--rule);
  padding: 6px;
  box-shadow:
    0 1px 0 rgba(255,255,255,0.4) inset,
    0 30px 60px -22px rgba(40, 75, 64, 0.3),
    0 18px 36px -18px rgba(40, 38, 33, 0.18),
    -20px 0 50px -32px rgba(61, 107, 92, 0.35);
}
.hero-portrait-big .frame img { width: 100%; height: 100%; object-fit: cover; display: block; }
.hero-portrait-big .caption {
  margin-top: 18px;
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--bronze);
  font-weight: 500;
  text-align: center;
  font-family: 'Inter', sans-serif;
}
.hero-portrait-big .caption .sub {
  display: block;
  color: var(--ink-mute);
  font-size: 12px;
  letter-spacing: 0.08em;
  margin-top: 5px;
  text-transform: none;
  font-style: italic;
  font-family: 'EB Garamond', serif;
  font-weight: 400;
}
@media (max-width: 980px) {
  .hero { padding: 56px 0 64px; }
  .hero-grid { grid-template-columns: 1fr; gap: 40px; }
  .hero-feature { order: -1; }
  .hero-portrait-big { width: 240px; }
  .hero-portrait-big .frame { width: 240px; height: 240px; }
}
@media (max-width: 520px) {
  .hero { padding: 40px 0 48px; }
  .hero-portrait-big { width: 200px; }
  .hero-portrait-big .frame { width: 200px; height: 200px; }
  .role-chips span { font-size: 11.5px; padding: 5px 12px; }
}

/* ─── featured strip ─── */
.featured {
  padding: 80px 0;
  border-bottom: 1px solid var(--rule);
  background: var(--paper);
}
.featured-head {
  display: flex;
  justify-content: space-between;
  align-items: end;
  margin-bottom: 36px;
  gap: 24px;
}
.featured-head h2 {
  font-size: clamp(28px, 3vw, 40px);
  margin: 0;
  line-height: 1.1;
  font-weight: 400;
}
.featured-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}
.featured-card {
  background: var(--paper-card);
  border: 1px solid var(--rule);
  padding: 28px 26px 26px;
  display: flex;
  flex-direction: column;
  transition: border-color .2s, transform .2s, background .2s, box-shadow .2s;
  text-decoration: none;
  position: relative;
  min-height: 280px;
}
.featured-card:hover {
  border-color: var(--jade);
  background: var(--paper-card-hover);
  transform: translateY(-3px);
  box-shadow: 0 8px 22px -10px rgba(40, 75, 64, 0.18);
}
.featured-card .tag {
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--bronze);
  margin-bottom: 14px;
  font-weight: 500;
  font-family: 'Inter', sans-serif;
}
.featured-card h3 {
  font-family: 'EB Garamond', serif;
  font-size: 22px;
  line-height: 1.22;
  margin: 0 0 12px;
  color: var(--ink);
  font-weight: 400;
  flex: 1;
}
.featured-card p {
  font-size: 13.5px;
  color: var(--ink-mute);
  margin: 0 0 16px;
  line-height: 1.5;
}
.featured-card .link {
  font-size: 13px;
  color: var(--jade);
  font-weight: 500;
  margin-top: auto;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-family: 'Inter', sans-serif;
}
.featured-card .link::after { content: "→"; transition: transform .15s; }
.featured-card:hover .link::after { transform: translateX(3px); }
@media (max-width: 1000px) { .featured-grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 540px) { .featured-grid { grid-template-columns: 1fr; } }

/* ─── section primitives ─── */
section.section {
  padding: 96px 0;
  border-bottom: 1px solid var(--rule);
  background: var(--paper);
}
section.section:last-of-type { border-bottom: 0; }
.section-head { margin-bottom: 48px; max-width: 760px; }
.section-title {
  font-size: clamp(32px, 4vw, 52px);
  line-height: 1.05;
  margin: 0 0 16px;
  font-weight: 400;
  letter-spacing: -0.012em;
}
.section-title .accent { color: var(--jade); font-style: italic; }
.section-lede { font-size: 18px; color: var(--ink-mute); line-height: 1.55; margin: 0; max-width: 640px; font-style: italic; font-family: 'EB Garamond', serif; }

/* ─── books ─── */
.book-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}
.book-card {
  background: var(--paper-card);
  border: 1px solid var(--rule);
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: 32px;
  padding: 36px;
  transition: border-color .2s, background .2s, box-shadow .2s;
}
.book-card:hover { border-color: var(--jade); background: var(--paper-card-hover); box-shadow: 0 8px 22px -10px rgba(40, 75, 64, 0.18); }
.book-cover {
  width: 200px;
  background: var(--paper-elev);
  padding: 6px;
  border: 1px solid var(--rule);
  box-shadow:
    0 1px 0 rgba(255,255,255,0.6) inset,
    0 12px 24px -12px rgba(40, 38, 33, 0.22);
  display: block;
}
.book-cover img { width: 100%; height: auto; display: block; }
.oa-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--jade);
  font-weight: 600;
  margin-bottom: 14px;
  font-family: 'Inter', sans-serif;
}
.oa-pill::before {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--jade);
  box-shadow: 0 0 0 4px var(--jade-glow);
}
.book-card h3 {
  font-size: 26px;
  line-height: 1.18;
  margin: 0 0 10px;
  font-weight: 400;
}
.book-meta { font-size: 13px; color: var(--ink-mute); margin-bottom: 16px; line-height: 1.5; }
.book-card p { font-size: 14.5px; color: var(--ink-soft); line-height: 1.6; margin: 0 0 18px; }
.book-links { display: flex; flex-wrap: wrap; gap: 18px; font-size: 13px; }
.book-links a { color: var(--jade); font-weight: 500; }
@media (max-width: 960px) { .book-grid { grid-template-columns: 1fr; } }
@media (max-width: 600px) {
  .book-card { grid-template-columns: 140px 1fr; gap: 22px; padding: 26px; }
  .book-cover { width: 140px; }
}

/* ─── research areas (editorial carousel — six chapters) ─── */
.research-grid {
  display: flex;
  gap: 24px;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  padding: 8px 32px 32px;
  margin: 0 -32px 24px;
  scrollbar-width: thin;
  scrollbar-color: var(--bronze-soft) transparent;
}
.research-grid::-webkit-scrollbar { height: 8px; }
.research-grid::-webkit-scrollbar-thumb { background: var(--bronze-soft); border-radius: 4px; }
.research-card {
  position: relative;
  overflow: hidden;
  background: var(--paper-card);
  border: 1px solid var(--rule);
  padding: 48px 44px 40px;
  transition: border-color .2s, background .2s, transform .2s, box-shadow .25s;
  display: flex;
  flex-direction: column;
  text-decoration: none;
  min-height: 400px;
  isolation: isolate;
  flex: 0 0 540px;
  scroll-snap-align: start;
}
.research-card:hover {
  border-color: var(--jade);
  transform: translateY(-3px);
  box-shadow: 0 16px 36px -16px rgba(40, 75, 64, 0.25);
}
.research-card .ghost-num {
  position: absolute;
  bottom: -38px;
  right: -16px;
  font-family: 'EB Garamond', serif;
  font-size: 280px;
  font-weight: 400;
  line-height: 0.85;
  color: var(--jade);
  opacity: 0.08;
  pointer-events: none;
  user-select: none;
  z-index: 0;
  letter-spacing: -0.04em;
  transition: opacity .25s, transform .25s;
}
.research-card:hover .ghost-num {
  opacity: 0.14;
  transform: translate(-4px, -4px);
}
.research-card .num {
  position: relative;
  z-index: 1;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.22em;
  color: var(--bronze);
  margin-bottom: 18px;
  font-family: 'Inter', sans-serif;
  display: inline-flex;
  align-items: center;
  gap: 12px;
}
.research-card .num::after {
  content: "";
  width: 36px;
  height: 1px;
  background: var(--bronze);
  opacity: 0.5;
}
.research-card h4 {
  position: relative;
  z-index: 1;
  font-family: 'EB Garamond', serif;
  font-size: clamp(24px, 2.4vw, 30px);
  line-height: 1.15;
  margin: 0 0 18px;
  font-weight: 400;
  color: var(--ink);
  letter-spacing: -0.01em;
}
.research-card p {
  position: relative;
  z-index: 1;
  font-size: 16px;
  color: var(--ink-soft);
  line-height: 1.6;
  margin: 0 0 22px;
  flex: 1;
}
.research-card .card-link {
  position: relative;
  z-index: 1;
  font-size: 12.5px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--jade);
  font-weight: 600;
  margin-top: auto;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: 'Inter', sans-serif;
}
.research-card .card-link::after {
  content: "→";
  transition: transform .15s;
  letter-spacing: 0;
}
.research-card:hover .card-link::after { transform: translateX(4px); }

/* Inverted jade variant — checkerboard alternation */
.research-card.invert {
  background: linear-gradient(135deg, #4f8270 0%, #3d6b5c 60%, #2f5547 100%);
  border-color: var(--jade-deep);
  color: var(--paper);
}
.research-card.invert:hover {
  border-color: var(--paper);
  box-shadow: 0 16px 36px -16px rgba(40, 75, 64, 0.45);
}
.research-card.invert .ghost-num { color: var(--paper); opacity: 0.13; }
.research-card.invert:hover .ghost-num { opacity: 0.22; }
.research-card.invert .num { color: var(--paper); opacity: 0.78; }
.research-card.invert .num::after { background: var(--paper); opacity: 0.5; }
.research-card.invert h4 { color: var(--paper); }
.research-card.invert p { color: var(--paper); opacity: 0.88; }
.research-card.invert .card-link { color: var(--paper); }

@media (max-width: 1100px) {
  .research-card { flex: 0 0 460px; padding: 44px 38px 36px; min-height: 380px; }
}
@media (max-width: 760px) {
  .research-grid { gap: 14px; padding: 8px 20px 24px; margin: 0 -20px 24px; }
  .research-card {
    flex: 0 0 min(86vw, 340px);
    padding: 36px 30px 32px;
    min-height: 360px;
  }
  .research-card .ghost-num { font-size: 220px; bottom: -28px; right: -12px; }
  .research-card h4 { font-size: 24px; }
  .research-card p { font-size: 15px; }
}

/* ─── inverted jade feature (qi-tological) ─── */
.qi-feature {
  background: linear-gradient(135deg, #4f8270 0%, #3d6b5c 60%, #2f5547 100%);
  border: 1px solid var(--jade-deep);
  padding: 56px 56px 52px;
  position: relative;
  overflow: hidden;
  color: var(--paper);
}
.qi-feature::before {
  content: "氣";
  position: absolute;
  top: 50%;
  right: -40px;
  transform: translateY(-50%);
  font-family: 'EB Garamond', serif;
  font-size: 420px;
  font-weight: 400;
  color: var(--paper);
  opacity: 0.07;
  line-height: 1;
  pointer-events: none;
  user-select: none;
}
.qi-feature .qi-eyebrow {
  font-size: 11px;
  letter-spacing: 0.22em;
  color: var(--paper);
  text-transform: uppercase;
  font-weight: 500;
  margin-bottom: 14px;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  opacity: 0.78;
  font-family: 'Inter', sans-serif;
}
.qi-feature .qi-eyebrow::before {
  content: "";
  width: 12px;
  height: 1px;
  background: var(--paper);
  opacity: 0.6;
}
.qi-feature h3 {
  font-size: clamp(28px, 3.6vw, 40px);
  margin: 0 0 18px;
  color: var(--paper);
  font-weight: 400;
  line-height: 1.12;
  letter-spacing: -0.012em;
  max-width: 780px;
  position: relative;
  font-family: 'EB Garamond', serif;
}
.qi-feature h3 .accent { color: var(--paper-deep); font-style: italic; }
.qi-feature p {
  margin: 0;
  color: var(--paper);
  opacity: 0.92;
  font-size: 17px;
  line-height: 1.65;
  max-width: 760px;
  position: relative;
}
.qi-feature p em { color: var(--paper); font-style: italic; font-weight: 500; opacity: 1; }

/* ─── articles (carousel) ─── */
.carousel-wrap { position: relative; margin: 0 -32px; }
.carousel {
  display: flex;
  gap: 18px;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  padding: 8px 32px 28px;
  scrollbar-width: thin;
  scrollbar-color: var(--bronze) transparent;
}
.carousel::-webkit-scrollbar { height: 8px; }
.carousel::-webkit-scrollbar-thumb { background: var(--bronze-soft); border-radius: 4px; }
.article-card {
  flex: 0 0 320px;
  scroll-snap-align: start;
  background: var(--paper-card);
  border: 1px solid var(--rule);
  padding: 28px 26px 26px;
  display: flex;
  flex-direction: column;
  transition: border-color .2s, background .2s, transform .2s, box-shadow .2s;
}
.journal-cover {
  width: 84px;
  height: 118px;
  display: block;
  margin: 0 0 22px;
  background: var(--paper-elev);
  border: 1px solid var(--rule);
  box-shadow:
    0 1px 0 rgba(255,255,255,0.5) inset,
    0 6px 14px -6px rgba(40, 38, 33, 0.28),
    0 3px 6px -3px rgba(40, 38, 33, 0.18);
  flex-shrink: 0;
  transition: transform .2s;
}
.journal-cover img { width: 100%; height: 100%; object-fit: cover; display: block; }
.article-card:hover .journal-cover { transform: translateY(-2px) rotate(-1.5deg); }
.article-card:hover {
  border-color: var(--jade);
  background: var(--paper-card-hover);
  transform: translateY(-2px);
  box-shadow: 0 8px 22px -10px rgba(40, 75, 64, 0.18);
}
.article-card .journal {
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--bronze);
  margin-bottom: 12px;
  font-weight: 600;
  font-family: 'Inter', sans-serif;
}
.article-card h4 {
  font-size: 18px;
  line-height: 1.3;
  margin: 0 0 12px;
  flex: 1;
  font-weight: 400;
  color: var(--ink);
}
.article-card .meta { font-size: 13px; color: var(--ink-mute); margin-bottom: 14px; font-style: italic; }
.article-card .doi { font-size: 12px; color: var(--jade); font-weight: 600; align-self: flex-start; font-family: 'Inter', sans-serif; }

.pubs-toggle {
  margin-top: 28px;
  font-family: 'Inter', sans-serif;
  font-size: 13px;
  letter-spacing: 0.08em;
  border: 1px solid var(--rule);
  background: transparent;
  color: var(--ink-soft);
  cursor: pointer;
  padding: 12px 22px;
  border-radius: 999px;
  transition: border-color .15s, color .15s, background .15s;
  font-weight: 500;
}
.pubs-toggle:hover { border-color: var(--jade); color: var(--paper); background: var(--jade); }

.pubs-full {
  display: none;
  margin-top: 32px;
  background: var(--paper-card);
  border: 1px solid var(--rule);
  padding: 44px 48px;
}
.pubs-full.open { display: block; }
.pubs-full h3 {
  font-family: 'Inter', sans-serif;
  font-size: 11px;
  margin: 0 0 16px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--bronze);
  font-weight: 600;
}
.pubs-full h3:not(:first-child) { margin-top: 36px; }
.pubs-full ol {
  padding-left: 28px;
  margin: 0;
  font-size: 14.5px;
  line-height: 1.6;
}
.pubs-full ol li { padding: 6px 0; color: var(--ink-soft); }
.pubs-full em { color: var(--ink); font-style: italic; }
.pubs-full a { color: var(--jade); border-bottom: 1px solid var(--rule); }
.pubs-full a:hover { color: var(--jade-deep); border-bottom-color: var(--jade); }

/* ─── lectures (carousel of video cards) ─── */
.video-card {
  flex: 0 0 340px;
  scroll-snap-align: start;
  background: var(--paper-card);
  border: 1px solid var(--rule);
  display: flex;
  flex-direction: column;
  cursor: pointer;
  transition: border-color .2s, transform .2s, background .2s, box-shadow .2s;
}
.video-card:hover {
  border-color: var(--jade);
  background: var(--paper-card-hover);
  transform: translateY(-2px);
  box-shadow: 0 8px 22px -10px rgba(40, 75, 64, 0.18);
}
.video-thumb {
  position: relative;
  aspect-ratio: 16 / 9;
  background: var(--ink);
  overflow: hidden;
}
.video-thumb img {
  width: 100%; height: 100%;
  object-fit: cover;
  display: block;
  transition: transform .3s;
}
.video-card:hover .video-thumb img { transform: scale(1.03); }
.play-btn {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 52px;
  height: 52px;
  margin: -26px 0 0 -26px;
  border-radius: 50%;
  background: rgba(244, 237, 224, 0.95);
  border: 1px solid var(--jade);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background .15s, transform .15s;
}
.video-card:hover .play-btn { background: var(--jade); transform: scale(1.05); }
.video-card:hover .play-btn::before { border-left-color: var(--paper); }
.play-btn::before {
  content: "";
  width: 0; height: 0;
  border-style: solid;
  border-width: 8px 0 8px 13px;
  border-color: transparent transparent transparent var(--jade-deep);
  margin-left: 3px;
}
.video-meta { padding: 16px 20px 18px; }
.video-date {
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--bronze);
  margin-bottom: 6px;
  font-weight: 600;
  font-family: 'Inter', sans-serif;
}
.video-title {
  font-family: 'EB Garamond', serif;
  font-size: 17px;
  line-height: 1.3;
  color: var(--ink);
  margin: 0;
  font-weight: 400;
}
.video-venue { font-size: 12.5px; color: var(--ink-mute); margin-top: 8px; font-style: italic; }

/* ─── talks (carousel) ─── */
.talk-card {
  flex: 0 0 320px;
  scroll-snap-align: start;
  background: var(--paper-card);
  border: 1px solid var(--rule);
  padding: 26px;
  display: flex;
  flex-direction: column;
  transition: border-color .2s, background .2s, box-shadow .2s;
}
.talk-card:hover { border-color: var(--jade); background: var(--paper-card-hover); box-shadow: 0 8px 22px -10px rgba(40, 75, 64, 0.18); }
.talk-card .date {
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--bronze);
  margin-bottom: 12px;
  font-weight: 600;
  font-family: 'Inter', sans-serif;
}
.talk-card h4 {
  font-size: 17px;
  line-height: 1.35;
  margin: 0 0 14px;
  flex: 1;
  font-weight: 400;
  color: var(--ink);
}
.talk-card .venue { font-size: 13px; color: var(--ink-mute); line-height: 1.45; font-style: italic; }

/* ─── teaching ─── */
.teaching-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}
/* Inverted bronze treatment for the flagship */
.teaching-flagship {
  grid-column: 1 / -1;
  background: linear-gradient(135deg, #a48043 0%, #8a6a3a 60%, #6e542a 100%);
  border: 1px solid var(--bronze-deep);
  padding: 44px 48px;
  position: relative;
  overflow: hidden;
  color: var(--paper);
}
.teaching-flagship::before {
  content: "教";
  position: absolute;
  top: 50%;
  right: -20px;
  transform: translateY(-50%);
  font-family: 'EB Garamond', serif;
  font-size: 320px;
  font-weight: 400;
  color: var(--paper);
  opacity: 0.07;
  line-height: 1;
  pointer-events: none;
  user-select: none;
}
.teaching-flagship .eyebrow { margin-bottom: 14px; color: var(--paper); opacity: 0.85; }
.teaching-flagship .eyebrow::before { background: var(--paper); opacity: 0.6; }
.teaching-flagship h3 {
  font-size: clamp(24px, 2.6vw, 32px);
  margin: 0 0 14px;
  color: var(--paper);
  font-weight: 400;
  line-height: 1.18;
  position: relative;
}
.teaching-flagship p {
  margin: 0;
  color: var(--paper);
  opacity: 0.92;
  font-size: 16px;
  line-height: 1.6;
  max-width: 760px;
  position: relative;
}
.teaching-flagship p a {
  color: var(--paper);
  font-weight: 600;
  border-bottom: 1px solid rgba(244, 237, 224, 0.4);
}
.teaching-flagship p a:hover { color: var(--paper-deep); border-bottom-color: var(--paper-deep); }

.teaching-block {
  background: var(--paper-card);
  border: 1px solid var(--rule);
  padding: 28px 30px;
}
.teaching-block h3 {
  font-family: 'Inter', sans-serif;
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--bronze);
  margin: 0 0 16px;
  font-weight: 600;
}
.teaching-block ul { list-style: none; padding: 0; margin: 0; }
.teaching-block li {
  padding: 12px 0;
  border-bottom: 1px solid var(--rule-soft);
  font-size: 15px;
  line-height: 1.45;
  color: var(--ink-soft);
}
.teaching-block li:last-child { border-bottom: 0; }
.teaching-block em { color: var(--ink); font-style: italic; }
.teaching-block .inst { display: block; font-size: 12.5px; color: var(--ink-mute); margin-top: 4px; font-style: italic; }
@media (max-width: 780px) { .teaching-grid { grid-template-columns: 1fr; } }

/* ─── events ─── */
.events-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; }
.event-card {
  background: var(--paper-card);
  border: 1px solid var(--rule);
  padding: 30px 32px;
  transition: border-color .2s, background .2s, box-shadow .2s;
}
.event-card:hover { border-color: var(--jade); background: var(--paper-card-hover); box-shadow: 0 8px 22px -10px rgba(40, 75, 64, 0.18); }
.event-card .date {
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--bronze);
  margin-bottom: 12px;
  font-weight: 600;
  font-family: 'Inter', sans-serif;
}
.event-card h4 { font-size: 21px; margin: 0 0 10px; line-height: 1.25; font-weight: 400; color: var(--ink); }
.event-card .meta { font-size: 14px; color: var(--ink-mute); line-height: 1.5; font-style: italic; }
.event-card .role {
  font-size: 11px;
  color: var(--jade);
  letter-spacing: 0.16em;
  margin-top: 14px;
  text-transform: uppercase;
  font-weight: 600;
  font-family: 'Inter', sans-serif;
}
@media (max-width: 760px) { .events-grid { grid-template-columns: 1fr; } }

/* ─── contact ─── */
.contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 64px; align-items: start; }
.contact-block h3 {
  font-family: 'Inter', sans-serif;
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--bronze);
  margin: 0 0 18px;
  font-weight: 600;
}
.contact-email {
  font-family: 'EB Garamond', serif;
  font-size: 32px;
  display: inline-block;
  margin-bottom: 10px;
  color: var(--ink);
  font-weight: 400;
  letter-spacing: -0.005em;
}
.contact-email:hover { color: var(--jade); }
.contact-block ul { list-style: none; padding: 0; margin: 0; }
.contact-block li { padding: 8px 0; font-size: 15px; }
.contact-block li a { color: var(--ink-soft); }
.contact-block li a:hover { color: var(--jade); }
@media (max-width: 760px) { .contact-grid { grid-template-columns: 1fr; gap: 36px; } }

/* ─── footer (deep jade, continues seamlessly from contact) ─── */
footer.site-footer {
  background: linear-gradient(180deg, #152d24 0%, #0a1814 100%);
  color: var(--paper);
  padding: 56px 0 48px;
  border-top: 0;
  font-size: 13px;
}
footer.site-footer .container { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 16px; align-items: center; }
footer.site-footer a { color: var(--paper); }
footer.site-footer a:hover { color: #d4a85a; }
footer.site-footer .copyright { opacity: 0.78; }

/* ─── video modal ─── */
.video-modal {
  position: fixed; inset: 0;
  background: rgba(26, 24, 24, 0.92);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 100;
  padding: 28px;
}
.video-modal.open { display: flex; }
.video-modal-frame {
  width: min(960px, 100%);
  aspect-ratio: 16 / 9;
  background: #000;
  position: relative;
}
.video-modal iframe { width: 100%; height: 100%; border: 0; display: block; }
.video-modal-close {
  position: absolute;
  top: -40px;
  right: 0;
  background: transparent;
  border: 0;
  color: var(--paper);
  font-size: 14px;
  letter-spacing: 0.12em;
  cursor: pointer;
  font-family: 'Inter', sans-serif;
  text-transform: uppercase;
}
.video-modal-close:hover { color: var(--jade-soft); }

/* ─── version switcher ─── */
.version-switch {
  position: fixed;
  bottom: 20px;
  right: 20px;
  background: var(--ink);
  border: 1px solid var(--ink);
  padding: 6px;
  display: flex;
  gap: 4px;
  z-index: 200;
  border-radius: 999px;
  box-shadow: 0 8px 32px rgba(0,0,0,0.25);
  font-size: 13px;
  letter-spacing: 0.06em;
  font-family: 'Inter', sans-serif;
}
.version-switch a {
  display: inline-block;
  padding: 8px 16px;
  color: var(--paper);
  text-decoration: none;
  background: transparent;
  border-radius: 999px;
  transition: background .15s, color .15s;
  font-weight: 500;
}
.version-switch a:hover { background: rgba(255,255,255,0.06); color: var(--paper); }
.version-switch a.active {
  background: var(--jade);
  color: var(--paper);
  pointer-events: none;
  cursor: default;
}

/* ───────────────── parchment section (Writing) ───────────────── */

.section.section-parchment {
  background: linear-gradient(135deg, #f1e7cd 0%, #ebdfbe 60%, #e4d6ab 100%);
  border-top: 1px solid #c9b88a;
  border-bottom: 1px solid #c9b88a;
  color: var(--ink);
  position: relative;
  overflow: hidden;
}
.section.section-parchment::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 85% 15%, rgba(138, 106, 58, 0.10), transparent 55%),
    radial-gradient(circle at 8% 92%, rgba(94, 71, 36, 0.06), transparent 50%);
  pointer-events: none;
}
.section-parchment .eyebrow { color: var(--bronze-deep); opacity: 1; }
.section-parchment .eyebrow::before { background: var(--bronze-deep); opacity: 0.7; }
.section-parchment .section-title { color: var(--ink); }
.section-parchment .section-title .accent { color: var(--bronze); font-style: italic; }
.section-parchment .section-lede { color: var(--ink-soft); }

.section-parchment .article-card {
  background: #fdfaf0;
  border: 1px solid #d4c391;
  box-shadow: 0 6px 22px -10px rgba(94, 71, 36, 0.2);
}
.section-parchment .article-card:hover {
  border-color: var(--bronze);
  background: #fffdf5;
  transform: translateY(-3px);
  box-shadow: 0 12px 28px -10px rgba(94, 71, 36, 0.28);
}
.section-parchment .article-card .journal { color: var(--bronze-deep); font-weight: 600; }
.section-parchment .article-card h4 { color: var(--ink); }
.section-parchment .article-card .meta { color: var(--ink-mute); }
.section-parchment .article-card .doi { color: var(--bronze-deep); font-weight: 600; }

.section-parchment .carousel { scrollbar-color: var(--bronze) transparent; }
.section-parchment .carousel::-webkit-scrollbar-thumb { background: var(--bronze); }

.section-parchment .pubs-toggle {
  background: transparent;
  border: 1px solid var(--bronze);
  color: var(--bronze-deep);
}
.section-parchment .pubs-toggle:hover {
  background: var(--bronze);
  border-color: var(--bronze);
  color: var(--paper);
}

.section-parchment .pubs-full {
  background: #fdfaf0;
  border: 1px solid #d4c391;
}
.section-parchment .pubs-full h3 { color: var(--bronze-deep); font-weight: 600; }
.section-parchment .pubs-full ol li { color: var(--ink-soft); }
.section-parchment .pubs-full em { color: var(--ink); }
.section-parchment .pubs-full a { color: var(--bronze-deep); border-bottom: 1px solid #d4c391; }
.section-parchment .pubs-full a:hover { color: var(--ink); border-bottom-color: var(--ink); }

/* ───────────────── jade section (Conference Circuit / Talks) ───────────────── */

.section.section-jade {
  background: linear-gradient(135deg, #2f5547 0%, #1f3a30 55%, #142822 100%);
  border-top: 1px solid #0e1f1a;
  border-bottom: 1px solid #0e1f1a;
  color: var(--paper);
  position: relative;
  overflow: hidden;
}
.section.section-jade::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 85% 15%, rgba(255, 240, 200, 0.06), transparent 50%),
    radial-gradient(circle at 10% 95%, rgba(180, 140, 70, 0.05), transparent 45%);
  pointer-events: none;
}
.section-jade .eyebrow { color: #d4a85a; opacity: 1; }
.section-jade .eyebrow::before { background: #d4a85a; opacity: 0.85; }
.section-jade .section-title { color: #fbf6ec; opacity: 1; text-shadow: 0 1px 0 rgba(0,0,0,0.18); }
.section-jade .section-title .accent { color: #e8c878; font-style: italic; }
.section-jade .section-lede { color: #fbf6ec; opacity: 0.96; }

.section-jade .talk-card {
  background: var(--paper-card);
  border: 1px solid var(--rule);
  box-shadow: 0 6px 22px -10px rgba(0, 0, 0, 0.3);
}
.section-jade .talk-card:hover {
  border-color: #d4a85a;
  background: var(--paper-card-hover);
  transform: translateY(-3px);
  box-shadow: 0 12px 28px -10px rgba(0, 0, 0, 0.4);
}
.section-jade .talk-card .date { color: var(--bronze-deep); font-weight: 600; }
.section-jade .talk-card h4 { color: var(--ink); }
.section-jade .talk-card .venue { color: var(--ink-mute); }

.section-jade .carousel { scrollbar-color: #d4a85a transparent; }
.section-jade .carousel::-webkit-scrollbar-thumb { background: #d4a85a; }

/* ───────────────── bronze/gold section (Featured "What's new") ───────────────── */

.section-bronze {
  background: linear-gradient(135deg, #c8a85e 0%, #b89762 55%, #9c7e3a 100%);
  border-top: 1px solid #6e542a;
  border-bottom: 1px solid #6e542a;
  color: #1a1408;
  position: relative;
  overflow: hidden;
}
.section-bronze::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 85% 15%, rgba(255, 240, 200, 0.18), transparent 55%),
    radial-gradient(circle at 8% 92%, rgba(60, 40, 10, 0.08), transparent 50%);
  pointer-events: none;
}
.section-bronze .featured-head h2 {
  color: #1a1408;
  position: relative;
}
.section-bronze .featured-head .btn-arrow {
  color: #2a1f0a;
  font-weight: 600;
  position: relative;
}
.section-bronze .featured-head .btn-arrow:hover { color: #1a1408; }
.section-bronze .featured-card {
  background: #fdfaf0;
  border: 1px solid #8a6a3a;
  box-shadow: 0 8px 24px -12px rgba(40, 25, 0, 0.35);
}
.section-bronze .featured-card:hover {
  border-color: #1a1408;
  background: #fffdf5;
  transform: translateY(-3px);
  box-shadow: 0 14px 30px -14px rgba(40, 25, 0, 0.5);
}
.section-bronze .featured-card .tag {
  color: #5e4724;
  font-weight: 600;
}
.section-bronze .featured-card h3 { color: var(--ink); }
.section-bronze .featured-card p { color: var(--ink-soft); }
.section-bronze .featured-card .link { color: #5e4724; font-weight: 600; }

/* ───────────────── deep jade section (Contact, matches footer) ───────────────── */

.section.section-jade-deep {
  background: linear-gradient(180deg, #1f3a30 0%, #152d24 100%);
  border-top: 1px solid #0a1814;
  border-bottom: 0;
  color: var(--paper);
  position: relative;
  overflow: hidden;
}
.section.section-jade-deep::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 85% 15%, rgba(255, 240, 200, 0.05), transparent 55%);
  pointer-events: none;
}
.section-jade-deep .eyebrow { color: #d4a85a; opacity: 1; }
.section-jade-deep .eyebrow::before { background: #d4a85a; opacity: 0.85; }
.section-jade-deep .section-title { color: #fbf6ec; opacity: 1; text-shadow: 0 1px 0 rgba(0,0,0,0.18); }
.section-jade-deep .section-title .accent { color: #e8c878; font-style: italic; }
.section-jade-deep .section-lede { color: #fbf6ec; opacity: 0.95; }
.section-jade-deep .contact-block h3 { color: #d4a85a; }
.section-jade-deep .contact-email { color: var(--paper); }
.section-jade-deep .contact-email:hover { color: #d4a85a; }
.section-jade-deep .contact-block p { color: var(--paper); opacity: 0.78; }
.section-jade-deep .contact-block li a { color: var(--paper); opacity: 0.88; }
.section-jade-deep .contact-block li a:hover { color: #d4a85a; opacity: 1; }

/* ───────────────── warm khaki section (Teaching) ───────────────── */

.section.section-khaki {
  background: linear-gradient(135deg, #ece4cf 0%, #e3d9be 60%, #d9ceae 100%);
  border-top: 1px solid #bba87f;
  border-bottom: 1px solid #bba87f;
  color: var(--ink);
  position: relative;
  overflow: hidden;
}
.section.section-khaki::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 85% 15%, rgba(138, 106, 58, 0.08), transparent 55%);
  pointer-events: none;
}
.section-khaki .eyebrow { color: var(--bronze-deep); }
.section-khaki .eyebrow::before { background: var(--bronze-deep); opacity: 0.7; }
.section-khaki .section-title { color: var(--ink); }
.section-khaki .section-title .accent { color: var(--bronze); font-style: italic; }
.section-khaki .section-lede { color: var(--ink-soft); }
.section-khaki .teaching-block {
  background: #fdfaf0;
  border: 1px solid #c4b893;
  box-shadow: 0 4px 14px -8px rgba(94, 71, 36, 0.18);
}
.section-khaki .teaching-block h3 { color: var(--bronze-deep); }
.section-khaki .teaching-block li { border-bottom-color: #d4c391; }
.section-khaki .teaching-block li:last-child { border-bottom: 0; }

/* ───────────────── mobile pass ───────────────── */

@media (max-width: 760px) {
  body { font-size: 15.5px; line-height: 1.58; }
  .container { padding: 0 20px; }

  section.section { padding: 56px 0; }
  .featured { padding: 48px 0; }
  .section-head { margin-bottom: 32px; }

  .nav-row { padding: 12px 0; }
  .nav-brand { font-size: 17px; }
  .nav-toggle { font-size: 24px; padding: 8px 12px; min-width: 44px; min-height: 44px; }
  .nav-links a { padding: 14px 20px; font-size: 15px; }

  .hero h1 { margin-bottom: 16px; }
  .hero-tag { margin-bottom: 22px; }
  .hero-bio p { font-size: 15.5px; line-height: 1.6; }
  .role-chips { gap: 6px; margin-bottom: 24px; }

  .btn { padding: 14px 22px; font-size: 14.5px; }
  .hero-actions { gap: 10px; }
  .hero-actions .btn { flex: 1; min-width: 140px; justify-content: center; }

  .eyebrow { font-size: 11.5px; letter-spacing: 0.14em; margin-bottom: 16px; }

  .featured-head { flex-direction: column; align-items: flex-start; gap: 12px; margin-bottom: 24px; }
  .featured-card { padding: 24px 22px; min-height: 0; }
  .featured-card h3 { font-size: 20px; }

  .book-card { grid-template-columns: 1fr; padding: 24px; gap: 20px; }
  .book-cover { width: 160px; margin: 0 auto; }
  .book-card h3 { font-size: 22px; }
  .book-card .book-meta { font-size: 12.5px; }
  .book-links { gap: 14px; }

  .research-card { padding: 26px 24px 24px; min-height: 0; }
  .research-card h4 { font-size: 18px; }
  .research-card p { font-size: 13.5px; }

  .qi-feature { padding: 32px 26px 30px; }
  .qi-feature::before { font-size: 240px; right: -30px; }
  .qi-feature h3 { font-size: 24px; }
  .qi-feature p { font-size: 15.5px; }

  .carousel-wrap { margin: 0 -20px; }
  .carousel { padding: 8px 20px 20px; gap: 14px; }
  .article-card, .talk-card { flex: 0 0 280px; padding: 22px; }
  .article-card h4, .talk-card h4 { font-size: 16px; }

  .pubs-full { padding: 28px 22px; }
  .pubs-full ol { padding-left: 22px; font-size: 14px; }
  .pubs-full ol li { padding: 5px 0; }

  .video-card { flex: 0 0 300px; }
  .video-title { font-size: 15.5px; }
  .video-meta { padding: 14px 18px 16px; }

  .teaching-flagship { padding: 30px 26px; }
  .teaching-flagship::before { font-size: 200px; right: -20px; }
  .teaching-flagship h3 { font-size: 22px; }
  .teaching-block { padding: 22px 24px; }

  .event-card { padding: 24px 26px; }
  .event-card h4 { font-size: 19px; }

  .contact-email {
    font-size: clamp(22px, 6.4vw, 30px);
    word-break: break-word;
    line-height: 1.2;
  }

  .version-switch { bottom: 12px; right: 12px; padding: 4px; font-size: 12px; }
  .version-switch a { padding: 7px 12px; }

  .video-modal { padding: 20px; }
  .video-modal-close { top: -36px; font-size: 13px; padding: 8px 4px; }

  footer.site-footer { padding: 36px 0 32px; }
  footer.site-footer .container { flex-direction: column; align-items: flex-start; gap: 10px; }
}

@media (max-width: 380px) {
  body { font-size: 15px; }
  .container { padding: 0 16px; }
  .carousel-wrap { margin: 0 -16px; }
  .carousel { padding: 8px 16px 20px; }
  .hero-actions .btn { width: 100%; flex: none; }
  .role-chips span { font-size: 11px; padding: 5px 10px; }
}