:root {
  --bg: #000000;
  --surface-solid: #111113;
  --surface-soft: #f5f5f7;
  --text: #f5f5f7;
  --text-dark: #1d1d1f;
  --muted: #a1a1a6;
  --muted-dark: #5f6673;
  --line: rgba(255, 255, 255, 0.12);
  --line-light: rgba(0, 0, 0, 0.08);
  --blue: #0071e3;
  --blue-bright: #0a84ff;
  --shadow: 0 24px 70px rgba(0, 0, 0, 0.45);
  --radius: 30px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
p, h1, h2, h3 { margin-top: 0; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: saturate(180%) blur(20px);
  background: rgba(0, 0, 0, 0.72);
  border-bottom: 1px solid var(--line);
}
.nav {
  max-width: 1320px;
  margin: 0 auto;
  padding: 14px 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 14px;
}
.brand { font-weight: 600; letter-spacing: 0.01em; }
.nav-links { display: flex; gap: 28px; color: var(--muted); }
.nav-links a:hover { color: var(--text); }

.section {
  max-width: 1320px;
  margin: 0 auto;
  padding: 86px 28px;
}
.eyebrow, .section-kicker, .card-label {
  color: var(--blue-bright);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

.hero {
  min-height: 82vh;
  display: grid;
  grid-template-columns: 0.95fr 0.82fr;
  gap: 46px;
  align-items: center;
}
h1 {
  font-size: clamp(58px, 8vw, 112px);
  line-height: 0.96;
  letter-spacing: -0.07em;
  margin-bottom: 30px;
}
h2 {
  font-size: clamp(40px, 5.5vw, 72px);
  line-height: 1.02;
  letter-spacing: -0.055em;
  margin-bottom: 22px;
}
h3 {
  font-size: 28px;
  line-height: 1.12;
  letter-spacing: -0.035em;
  margin-bottom: 14px;
}
.lead {
  font-size: clamp(21px, 2.1vw, 30px);
  line-height: 1.3;
  letter-spacing: -0.035em;
  color: var(--muted);
  max-width: 760px;
}
.narrow { max-width: 760px; margin-left: auto; margin-right: auto; }
.hero-image-wrap {
  justify-self: center;
  width: min(100%, 590px);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  background: #efeff1;
  min-height: 420px;
}
.hero-image {
  width: 100%;
  height: 100%;
  min-height: 420px;
  object-fit: cover;
  object-position: center;
  display: block;
}

.two-column {
  display: grid;
  grid-template-columns: 0.82fr 1.18fr;
  gap: 82px;
  border-top: 1px solid var(--line);
}
.section-body {
  color: var(--muted);
  font-size: clamp(20px, 2.1vw, 28px);
  line-height: 1.55;
  letter-spacing: -0.035em;
}
.clean-list { padding-left: 24px; margin: 28px 0 0; }
.clean-list li { margin-bottom: 14px; }

.training-card {
  display: grid;
  grid-template-columns: 1fr 0.82fr;
  gap: 60px;
  align-items: center;
  padding: 68px;
  background: var(--surface-soft);
  color: var(--text-dark);
  border: 1px solid var(--line-light);
  border-radius: 42px;
  box-shadow: 0 24px 70px rgba(255,255,255,0.04);
}
.training-card .section-kicker { color: #3f4652; }
.training-card h2 { color: var(--blue); font-size: clamp(44px, 5.8vw, 78px); }
.training-intro {
  color: var(--muted-dark);
  font-size: clamp(20px, 2vw, 28px);
  line-height: 1.5;
  letter-spacing: -0.03em;
  margin-bottom: 26px;
}
.training-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}
.training-tags span {
  display: inline-flex;
  align-items: center;
  padding: 11px 18px;
  border: 1px solid rgba(0,0,0,0.1);
  border-radius: 999px;
  background: rgba(255,255,255,0.72);
  color: #333946;
  font-size: 16px;
  font-weight: 650;
  letter-spacing: -0.02em;
}
.training-photo-wrap {
  border-radius: 26px;
  overflow: hidden;
  box-shadow: 0 22px 50px rgba(0,0,0,0.16);
}
.training-photo {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  display: block;
}

.research-top { border-top: none; }
.publication-section { border-top: 1px solid var(--line); }
.section-heading-centered { text-align: center; max-width: 840px; margin: 0 auto 46px; }
.publication-list {
  display: grid;
  gap: 14px;
  max-width: 960px;
  margin: 0 auto;
}
.publication {
  padding: 24px 28px;
  background: var(--surface-solid);
  border: 1px solid var(--line);
  border-radius: 22px;
}
.pub-title {
  color: var(--text);
  font-size: 19px;
  line-height: 1.38;
  letter-spacing: -0.02em;
  margin-bottom: 8px;
}
.pub-meta {
  color: var(--muted);
  font-size: 15px;
  line-height: 1.35;
  letter-spacing: 0.01em;
  margin: 0;
}
.center-actions {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
  margin-top: 34px;
}
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 11px 20px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: rgba(255,255,255,0.06);
  color: var(--blue-bright);
  font-size: 16px;
  font-weight: 550;
  transition: transform 160ms ease, background 160ms ease, border-color 160ms ease;
}
.button:hover { transform: translateY(-1px); background: rgba(255,255,255,0.1); }

.peer-review-card {
  padding: 54px;
  background: var(--surface-solid);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.peer-review-card h2 { font-size: clamp(38px, 5vw, 64px); }
.peer-review-intro {
  color: var(--muted);
  font-size: 22px;
  line-height: 1.45;
  letter-spacing: -0.03em;
  max-width: 980px;
}
.journal-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin-top: 26px;
}
.journal-grid span, .hobby-grid span {
  padding: 12px 15px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: rgba(255,255,255,0.055);
  color: var(--muted);
  font-size: 15px;
  line-height: 1.25;
}

.medical-education-section { padding-top: 30px; }
.education-card {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 48px;
  align-items: start;
  padding: 54px;
  background: var(--surface-solid);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: 0 18px 55px rgba(0,0,0,0.22);
}
.education-card h2 {
  font-size: clamp(42px, 5.2vw, 72px);
  margin-bottom: 18px;
}
.education-intro {
  color: var(--muted);
  font-size: 22px;
  line-height: 1.45;
  letter-spacing: -0.03em;
  max-width: 650px;
  margin-bottom: 0;
}
.education-links {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}
.education-links a {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 18px;
  padding: 22px 24px;
  background: rgba(255,255,255,0.055);
  border: 1px solid var(--line);
  border-radius: 22px;
  transition: transform 160ms ease, background 160ms ease, border-color 160ms ease;
}
.education-links a:hover {
  transform: translateY(-2px);
  background: rgba(255,255,255,0.085);
  border-color: rgba(10,132,255,0.45);
}
.education-links span {
  color: var(--text);
  font-size: 20px;
  font-weight: 650;
  letter-spacing: -0.025em;
}
.education-links small {
  color: var(--muted);
  font-size: 14px;
  text-align: right;
  line-height: 1.3;
}

.cards { display: grid; gap: 22px; }
.cards.two { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.card {
  padding: 38px;
  background: var(--surface-solid);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: 0 18px 55px rgba(0,0,0,0.22);
}
.card p {
  color: var(--muted);
  font-size: 18px;
  line-height: 1.48;
  margin-bottom: 0;
}
.large-card { min-height: 255px; }
.hobby-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 24px;
}

.contact {
  text-align: center;
  border-top: 1px solid var(--line);
}
.contact-links {
  margin-top: 32px;
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  justify-content: center;
}
.contact-links a {
  padding: 10px 16px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: rgba(255,255,255,0.06);
  color: var(--blue-bright);
}

.site-footer {
  background: var(--surface-soft);
  color: var(--text-dark);
  padding: 56px 24px 42px;
  text-align: center;
}
.institution-logos {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 68px;
  flex-wrap: wrap;
  margin-bottom: 30px;
}
.institution-logos img {
  max-height: 62px;
  max-width: 340px;
  object-fit: contain;
  opacity: 0.95;
  transition: opacity 0.2s ease, transform 0.2s ease;
}
.institution-logos a:hover img { opacity: 1; transform: translateY(-2px); }
.site-footer p {
  color: #222833;
  font-size: 18px;
  letter-spacing: -0.02em;
  margin-bottom: 0;
}

@media (max-width: 980px) {
  .hero, .two-column, .training-card, .education-card, .cards.two { grid-template-columns: 1fr; }
  .section { padding: 68px 22px; }
  .hero { min-height: unset; padding-top: 58px; }
  .hero-image-wrap { width: min(100%, 520px); min-height: 380px; }
  .hero-image { min-height: 380px; }
  .two-column { gap: 30px; }
  .training-card, .education-card { padding: 36px; gap: 34px; }
  .journal-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 640px) {
  .nav-links { display: none; }
  .section { padding: 58px 18px; }
  h1 { font-size: clamp(54px, 16vw, 78px); }
  .lead { font-size: 22px; }
  .training-card, .peer-review-card, .education-card, .card { padding: 26px; border-radius: 26px; }
  .training-tags span, .journal-grid span, .hobby-grid span { font-size: 14px; }
  .journal-grid, .hobby-grid { grid-template-columns: 1fr; }
  .education-links a { flex-direction: column; align-items: flex-start; }
  .education-links small { text-align: left; }
  .institution-logos { gap: 30px; }
  .institution-logos img { max-width: 280px; max-height: 54px; }
}


/* v6: light About section and combined Research/Publications */
.about-section {
  max-width: none;
  width: 100%;
  background: linear-gradient(180deg, #f5f5f7 0%, #ffffff 100%);
  color: var(--text-dark);
  border-top: none;
  padding-left: max(28px, calc((100vw - 1320px) / 2 + 28px));
  padding-right: max(28px, calc((100vw - 1320px) / 2 + 28px));
}
.about-section h2 { color: #111827; }
.about-section .section-body { color: #5f6673; }
.about-section .section-kicker { color: var(--blue); }

.research-combined {
  border-top: 1px solid var(--line);
}
.research-top-inner {
  border-top: none;
  padding: 0;
  max-width: none;
}
.publication-block {
  padding-top: 92px;
  margin-top: 78px;
  border-top: 1px solid var(--line);
}
.research-peer-card {
  margin-top: 58px;
}

/* v7: light Apple-style home hero and Tim Hou-style contact section */
.site-header {
  background: rgba(245, 245, 247, 0.78);
  border-bottom: 1px solid rgba(0, 0, 0, 0.08);
}
.site-header .brand { color: #1d1d1f; }
.site-header .nav-links { color: #5f6673; }
.site-header .nav-links a:hover { color: #1d1d1f; }

.hero {
  max-width: none;
  width: 100%;
  min-height: calc(100vh - 50px);
  background: radial-gradient(circle at 70% 30%, rgba(255,255,255,0.92) 0%, rgba(245,245,247,0.96) 42%, #f5f5f7 100%);
  color: #111827;
  padding-left: max(28px, calc((100vw - 1320px) / 2 + 28px));
  padding-right: max(28px, calc((100vw - 1320px) / 2 + 28px));
}
.hero .eyebrow { color: var(--blue); }
.hero h1 { color: #111827; }
.hero .lead { color: #5f6673; }
.hero-image-wrap {
  width: min(100%, 520px);
  min-height: 360px;
  box-shadow: 0 26px 75px rgba(0,0,0,0.12);
  border: 1px solid rgba(0,0,0,0.06);
}
.hero-image { min-height: 360px; }

.contact-tim-style {
  text-align: left;
  border-top: 1px solid var(--line);
  max-width: none;
  width: 100%;
  padding-left: max(28px, calc((100vw - 1320px) / 2 + 28px));
  padding-right: max(28px, calc((100vw - 1320px) / 2 + 28px));
  padding-top: 110px;
  padding-bottom: 110px;
}
.contact-tim-style h2 {
  max-width: 1060px;
  font-size: clamp(38px, 5.6vw, 78px);
  line-height: 1.04;
  letter-spacing: -0.06em;
  margin-bottom: 46px;
}
.contact-email {
  display: inline-block;
  color: var(--text);
  font-size: clamp(30px, 3.9vw, 58px);
  line-height: 1.1;
  letter-spacing: -0.045em;
  border-bottom: 2px solid rgba(255,255,255,0.42);
  margin-bottom: 34px;
}
.contact-email:hover { color: var(--blue-bright); border-bottom-color: var(--blue-bright); }
.contact-tim-style .contact-links {
  justify-content: flex-start;
  gap: 24px;
  margin-top: 0;
}
.contact-tim-style .contact-links a {
  padding: 0;
  border: 0;
  background: transparent;
  color: var(--muted);
  font-size: 20px;
  font-weight: 750;
  letter-spacing: -0.025em;
}
.contact-tim-style .contact-links a:hover { color: var(--text); }

@media (max-width: 980px) {
  .hero { min-height: unset; }
  .hero-image-wrap { width: min(100%, 440px); min-height: 320px; }
  .hero-image { min-height: 320px; }
}

@media (max-width: 640px) {
  .hero { padding-top: 62px; }
  .contact-tim-style { padding-top: 76px; padding-bottom: 80px; }
  .contact-tim-style .contact-links { flex-direction: column; gap: 14px; align-items: flex-start; }
}

/* v8: About section back to black background */
.about-section {
  background: #000000;
  color: var(--text);
}
.about-section h2 { color: var(--text); }
.about-section .section-body { color: var(--muted); }
.about-section .section-kicker { color: var(--blue-bright); }

/* v10: mailto contact button */
.contact-message-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  appearance: none;
  border: 0;
  background: transparent;
  color: var(--text);
  font: inherit;
  font-size: clamp(34px, 4.8vw, 72px);
  line-height: 1.05;
  letter-spacing: -0.055em;
  font-weight: 800;
  border-bottom: 2px solid rgba(255,255,255,0.42);
  padding: 0 0 8px;
  margin-bottom: 18px;
  cursor: pointer;
  text-decoration: none;
}

.contact-message-button:hover,
.contact-message-button:focus-visible {
  color: var(--blue-bright);
  border-bottom-color: var(--blue-bright);
  outline: none;
}
.contact-note {
  color: var(--muted);
  font-size: 18px;
  margin: 0 0 34px;
}