/* ============================================================
   BASE & TOKENS
   ============================================================ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:         #ffffff;
  --bg-2:       #f8fafc;
  --bg-3:       #f1f5f9;
  --surface:    #ffffff;
  --surface-hov: #f8fafc;
  --border:     rgba(15, 23, 42, 0.08);
  --border-hov: rgba(15, 23, 42, 0.2);

  --accent:     #522d80;
  --accent-dim: rgba(82, 45, 128, 0.06);
  --accent-glow: rgba(82, 45, 128, 0.15);
  --gold:       #f56600;
  --gold-dim:   rgba(245, 102, 0, 0.1);

  --text-1:    #0f172a;
  --text-2:    #475569;
  --text-3:    #64748b;

  --font-sans: 'Inter', system-ui, sans-serif;
  --font-serif: 'EB Garamond', Georgia, serif;
  --font-mono: 'JetBrains Mono', monospace;

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;

  --transition: 0.25s cubic-bezier(0.4,0,0.2,1);
  --transition-slow: 0.5s cubic-bezier(0.4,0,0.2,1);
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text-1);
  line-height: 1.7;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }

/* ============================================================
   EDUCATION
   ============================================================ */
.edu-list {
  display: flex;
  flex-direction: column;
  gap: 0;
  border-left: 2px solid var(--border);
  margin: 4px 0 20px 4px;
  padding-left: 20px;
}
.edu-item {
  position: relative;
  padding-bottom: 16px;
}
.edu-item::before {
  content: '';
  position: absolute;
  left: -25px; top: 7px;
  width: 7px; height: 7px;
  background: var(--accent);
  border-radius: 50%;
  box-shadow: 0 0 8px var(--accent-glow);
}
.edu-item:last-child { padding-bottom: 0; }
.edu-degree {
  font-size: 0.93rem;
  color: var(--text-1);
  font-weight: 500;
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 8px;
}
.edu-year {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--accent);
  letter-spacing: 0.06em;
  font-weight: 400;
}
.edu-school {
  font-size: 0.9rem;
  color: var(--text-2);
  font-weight: 500;
  margin-top: 3px;
}
.edu-loc {
  font-size: 0.78rem;
  color: var(--text-3);
  font-weight: 400;
}

/* ============================================================
   SCROLLBAR
   ============================================================ */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--bg-3); border-radius: 3px; }

/* ============================================================
   UTILS
   ============================================================ */
.container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 32px;
}

.section-label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 16px;
}

.section-heading {
  font-family: var(--font-serif);
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 500;
  line-height: 1.2;
  color: var(--text-1);
  margin-bottom: 20px;
}
.section-heading.centered { text-align: center; }

.section-subheading {
  text-align: center;
  color: var(--text-2);
  max-width: 560px;
  margin: 0 auto 60px;
  font-size: 1.05rem;
}

/* Buttons */
.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 32px;
  background: var(--accent);
  color: #ffffff;
  font-weight: 600;
  font-size: 0.92rem;
  border-radius: 50px;
  transition: var(--transition);
  letter-spacing: 0.02em;
}
.btn-primary:hover {
  background: #3b205d;
  transform: translateY(-2px);
  box-shadow: 0 12px 32px var(--accent-glow);
}

.btn-outline {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 30px;
  border: 1.5px solid var(--border);
  color: var(--text-2);
  font-size: 0.92rem;
  border-radius: 50px;
  transition: var(--transition);
  letter-spacing: 0.02em;
}
.btn-outline:hover {
  border-color: var(--accent);
  color: var(--accent);
  transform: translateY(-2px);
}

/* ============================================================
   NAV
   ============================================================ */
#navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  transition: var(--transition-slow);
  padding: 0 48px;
}
#navbar.scrolled {
  background: rgba(255,255,255,0.9);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  max-width: 1080px;
  margin: 0 auto;
  height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-logo {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--accent);
  letter-spacing: 0.05em;
}
.nav-links {
  display: flex;
  gap: 36px;
  list-style: none;
}
.nav-links a {
  font-size: 0.88rem;
  color: var(--text-2);
  letter-spacing: 0.03em;
  transition: var(--transition);
  position: relative;
}
.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px; left: 0;
  width: 0; height: 1.5px;
  background: var(--accent);
  transition: var(--transition);
}
.nav-links a:hover { color: var(--text-1); }
.nav-links a:hover::after { width: 100%; }

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}
.hamburger span {
  display: block;
  width: 22px; height: 2px;
  background: var(--text-2);
  border-radius: 2px;
  transition: var(--transition);
}

/* Mobile menu */
.mobile-menu {
  display: none;
  position: fixed;
  top: 68px; left: 0; right: 0;
  background: rgba(255,255,255,0.98);
  backdrop-filter: blur(20px);
  z-index: 99;
  flex-direction: column;
  padding: 24px 32px;
  gap: 4px;
  border-bottom: 1px solid var(--border);
  transform: translateY(-10px);
  opacity: 0;
  transition: var(--transition);
}
.mobile-menu.open {
  display: flex;
  transform: translateY(0);
  opacity: 1;
}
.mobile-link {
  padding: 12px 0;
  font-size: 1.05rem;
  color: var(--text-2);
  border-bottom: 1px solid var(--border);
  transition: var(--transition);
}
.mobile-link:last-child { border-bottom: none; }
.mobile-link:hover { color: var(--accent); padding-left: 8px; }

/* ============================================================
   HERO
   ============================================================ */
#hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
}
#mathCanvas {
  width: 100%; height: 100%;
  opacity: 0.35;
}

/* Gradient overlays */
#hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 70% at 50% -10%, rgba(99,182,255,0.1), transparent),
    radial-gradient(ellipse 60% 80% at -10% 80%, rgba(99,182,255,0.06), transparent),
    linear-gradient(to bottom, rgba(7,9,15,0.3) 0%, rgba(7,9,15,0.85) 100%);
  z-index: 1;
}

.hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  max-width: 750px;
  padding: 0 32px;
}

.hero-badge {
  display: inline-block;
  padding: 7px 18px;
  border: 1px solid var(--border);
  border-radius: 50px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  color: var(--accent);
  text-transform: uppercase;
  margin-bottom: 28px;
  background: var(--accent-dim);
  backdrop-filter: blur(8px);
  animation: fadeUp 0.8s ease both;
}

.hero-name {
  font-family: var(--font-serif);
  font-size: clamp(3.5rem, 8vw, 6.5rem);
  font-weight: 500;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--text-1);
  margin-bottom: 20px;
  animation: fadeUp 0.8s 0.1s ease both;
}

.hero-title {
  font-size: 1.15rem;
  color: var(--text-2);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 20px;
  font-weight: 400;
  animation: fadeUp 0.8s 0.2s ease both;
}

.hero-tagline {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-style: italic;
  color: var(--text-2);
  margin-bottom: 44px;
  max-width: 520px;
  margin-left: auto;
  margin-right: auto;
  animation: fadeUp 0.8s 0.3s ease both;
}

.hero-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
  animation: fadeUp 0.8s 0.4s ease both;
}

.hero-scroll {
  position: absolute;
  bottom: 40px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 2;
  animation: fadeIn 1.5s 1s ease both;
}
.scroll-indicator {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  color: var(--text-3);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}
.scroll-line {
  width: 1px; height: 48px;
  background: linear-gradient(to bottom, var(--text-3), transparent);
  animation: scrollPulse 2s ease-in-out infinite;
}
@keyframes scrollPulse {
  0%, 100% { opacity: 0.4; transform: scaleY(1); }
  50% { opacity: 1; transform: scaleY(1.1); }
}

/* ============================================================
   ABOUT
   ============================================================ */
#about {
  padding: 120px 0 60px;
  background: var(--bg-2);
  position: relative;
}
#about::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 1px;
  background: linear-gradient(to right, transparent, var(--border), transparent);
}

.about-grid {
  display: grid;
  grid-template-columns: 300px 1fr;
  gap: 64px;
  align-items: start;
}

.about-photo-wrap {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.about-photo-frame {
  width: 100%;
  aspect-ratio: 3/4;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border);
  background: var(--bg-3);
  position: relative;
}
.about-photo-placeholder {
  width: 100%; height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  color: var(--text-3);
  font-size: 0.8rem;
  letter-spacing: 0.08em;
}
.about-photo-placeholder svg {
  width: 80px; height: 80px;
}

.about-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}
.about-card-item {
  display: flex;
  align-items: center;
  gap: 14px;
}
.about-card-icon { font-size: 1.2rem; }
.about-card-label {
  font-size: 0.7rem;
  color: var(--text-3);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-family: var(--font-mono);
}
.about-card-value {
  font-size: 0.88rem;
  color: var(--text-1);
  font-weight: 500;
}

.about-bio {
  color: var(--text-2);
  font-size: 1.02rem;
  margin-bottom: 18px;
  line-height: 1.8;
}
.about-bio strong { color: var(--text-1); font-weight: 500; }

.about-interests {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 28px;
}
.interest-tag {
  padding: 6px 16px;
  background: var(--accent-dim);
  border: 1px solid rgba(99,182,255,0.2);
  border-radius: 50px;
  font-size: 0.8rem;
  color: var(--accent);
  letter-spacing: 0.04em;
  transition: var(--transition);
}
.interest-tag:hover {
  background: rgba(99,182,255,0.22);
  border-color: var(--accent);
}

.about-links {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}
.about-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 20px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  color: var(--text-2);
  transition: var(--transition);
}
.about-link:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-dim);
}

/* ============================================================
   RESEARCH
   ============================================================ */
#research {
  padding: 60px 0;
  background: var(--bg);
}

.research-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}

.research-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 36px 32px;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}
.research-card::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: var(--radius-lg);
  background: radial-gradient(ellipse at top left, var(--accent-dim), transparent 60%);
  opacity: 0;
  transition: var(--transition);
}
.research-card:hover {
  border-color: var(--border-hov);
  transform: translateY(-6px);
  box-shadow: 0 24px 48px rgba(15,23,42,0.1);
}
.research-card:hover::before { opacity: 1; }

.research-card-icon {
  font-family: var(--font-serif);
  font-size: 3rem;
  color: var(--accent);
  margin-bottom: 20px;
  line-height: 1;
  position: relative;
}
.research-card-title {
  font-family: var(--font-serif);
  font-size: 1.35rem;
  font-weight: 500;
  margin-bottom: 14px;
  color: var(--text-1);
}
.research-card-desc {
  color: var(--text-2);
  font-size: 0.93rem;
  line-height: 1.75;
  margin-bottom: 20px;
}
.research-card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.research-card-tags span {
  padding: 4px 12px;
  background: var(--bg-3);
  border-radius: 50px;
  font-size: 0.72rem;
  color: var(--text-3);
  letter-spacing: 0.05em;
  font-family: var(--font-mono);
}

/* ============================================================
   PUBLICATIONS
   ============================================================ */
#publications {
  padding: 60px 0;
  background: var(--bg-2);
}

.pubs-list {
  display: flex;
  flex-direction: column;
  gap: 0;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  margin-bottom: 40px;
}

.pub-item {
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: 28px;
  padding: 32px 36px;
  border-bottom: 1px solid var(--border);
  transition: var(--transition);
  position: relative;
}
.pub-item:last-child { border-bottom: none; }
.pub-item::before {
  content: '';
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 3px;
  background: var(--accent);
  opacity: 0;
  transition: var(--transition);
}
.pub-item:hover {
  background: var(--surface);
}
.pub-item:hover::before { opacity: 1; }

.pub-year {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--accent);
  padding-top: 4px;
  letter-spacing: 0.06em;
}
.pub-title {
  font-family: var(--font-serif);
  font-size: 1.1rem;
  font-weight: 500;
  color: var(--text-1);
  margin-bottom: 6px;
  line-height: 1.4;
}
.pub-authors {
  font-size: 0.88rem;
  color: var(--text-2);
  margin-bottom: 4px;
}
.pub-venue {
  font-size: 0.83rem;
  color: var(--text-3);
  font-style: italic;
  margin-bottom: 12px;
}
.pub-links { display: flex; gap: 10px; }
.pub-tag {
  padding: 4px 12px;
  background: var(--bg-3);
  border: 1px solid var(--border);
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--text-2);
  letter-spacing: 0.05em;
  transition: var(--transition);
}
.pub-tag:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-dim);
}

.pubs-footer { text-align: center; }

.talks-group { margin-bottom: 40px; }
.talks-group-label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--gold);
  margin-bottom: 16px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border);
}

/* ============================================================
   TEACHING
   ============================================================ */
#teaching {
  padding: 60px 0;
  background: var(--bg);
}

#talks {
  padding: 60px 0;
  background: var(--bg-2);
}

.teaching-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 28px;
}

.teaching-semester {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: var(--transition);
}
.teaching-semester:hover {
  border-color: var(--border-hov);
  box-shadow: 0 12px 32px rgba(15,23,42,0.1);
}

.semester-tag {
  background: var(--bg-3);
  border-bottom: 1px solid var(--border);
  padding: 14px 24px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
}

.course-list {
  padding: 8px 0;
}
.course-item {
  padding: 18px 24px;
  border-bottom: 1px solid var(--border);
  transition: var(--transition);
}
.course-item:last-child { border-bottom: none; }
.course-item:hover { background: var(--surface-hov); padding-left: 28px; }

.course-code {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--gold);
  letter-spacing: 0.08em;
  margin-bottom: 4px;
}
.course-name {
  font-weight: 500;
  color: var(--text-1);
  font-size: 0.95rem;
  margin-bottom: 4px;
}
.course-role {
  font-size: 0.77rem;
  color: var(--text-3);
  font-style: italic;
}

/* ============================================================
   CONTACT
   ============================================================ */
#contact {
  padding: 60px 0;
  background: var(--bg-2);
}

.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 24px;
}

.contact-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  text-align: center;
  transition: var(--transition);
}
.contact-card:hover {
  border-color: var(--border-hov);
  transform: translateY(-4px);
  box-shadow: 0 16px 40px rgba(15,23,42,0.1);
}

.contact-icon {
  width: 52px; height: 52px;
  background: var(--accent-dim);
  border: 1px solid rgba(99,182,255,0.2);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 20px;
}
.contact-icon svg {
  width: 22px; height: 22px;
  stroke: var(--accent);
}
.contact-label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-3);
  margin-bottom: 10px;
}
.contact-value {
  color: var(--text-1);
  font-size: 0.92rem;
  line-height: 1.8;
}
.contact-value a {
  color: var(--accent);
  transition: var(--transition);
}
.contact-value a:hover { color: #8fceff; text-decoration: underline; }

/* ============================================================
   FOOTER
   ============================================================ */
#footer {
  background: var(--bg);
  border-top: 1px solid var(--border);
  padding: 48px 32px;
  text-align: center;
}
.footer-name {
  font-family: var(--font-serif);
  font-size: 1.4rem;
  font-weight: 500;
  color: var(--text-1);
  margin-bottom: 8px;
}
.footer-affil {
  font-size: 0.85rem;
  color: var(--text-3);
  margin-bottom: 16px;
  letter-spacing: 0.04em;
}
.footer-copy {
  font-size: 0.78rem;
  color: var(--text-3);
  font-family: var(--font-mono);
}

/* ============================================================
   ANIMATIONS
   ============================================================ */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(24px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

/* Scroll-triggered fade-in */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 860px) {
  .about-grid {
    grid-template-columns: 1fr;
  }
  .about-photo-frame {
    max-width: 260px;
    aspect-ratio: 1/1;
    margin: 0 auto;
  }
  .about-photo-wrap { align-items: center; }
  .nav-links { display: none; }
  .hamburger { display: flex; }
  #navbar { padding: 0 24px; }
}

@media (max-width: 600px) {
  .container { padding: 0 20px; }
  #about, #research, #publications, #teaching, #contact {
    padding: 80px 0;
  }
  .pub-item { grid-template-columns: 1fr; }
  .pub-year { padding-bottom: 0; }
}