/* ================================================================
   STYLE.CSS — Prof. Lau Sian Lun — Teal & Amber Theme
   ================================================================ */

/* ===== CSS Variables — Light Theme ===== */
:root {
  --bg-primary: #fafbfc;
  --bg-secondary: #f0f4f3;
  --bg-tertiary: #e6edeb;
  --bg-card: #ffffff;
  --text-primary: #1a2e2a;
  --text-secondary: #4a635d;
  --text-muted: #7d9690;
  --border-color: #d4dfdb;
  --border-subtle: #e6edeb;
  --accent: #0d9488;
  --accent-hover: #0a7a70;
  --accent-soft: rgba(13, 148, 136, 0.07);
  --accent-soft-border: rgba(13, 148, 136, 0.18);
  --accent-gradient: linear-gradient(135deg, #0d9488, #0ea5e9);
  --warm: #d97706;
  --warm-soft: rgba(217, 119, 6, 0.08);
  --warm-border: rgba(217, 119, 6, 0.18);
  --navbar-bg: rgba(250, 251, 252, 0.88);
  --card-shadow: 0 1px 4px rgba(26, 46, 42, 0.05), 0 1px 2px rgba(26, 46, 42, 0.04);
  --card-shadow-hover: 0 12px 28px rgba(26, 46, 42, 0.1), 0 4px 10px rgba(26, 46, 42, 0.04);
  --footer-bg: #132622;
  --footer-text: #7d9690;
  --timeline-line: #d4dfdb;
  --timeline-dot: var(--accent);
  --hero-bg: linear-gradient(160deg, #f0f4f3 0%, #fafbfc 50%, #fef7ed 100%);
  --stats-bg: #132622;
  --stats-text: #c8d9d5;
  --stats-number: #5eead4;
}

/* ===== Dark Theme ===== */
[data-theme="dark"] {
  --bg-primary: #0c1615;
  --bg-secondary: #142120;
  --bg-tertiary: #1c2e2b;
  --bg-card: #1a2b28;
  --text-primary: #e0ece9;
  --text-secondary: #8faba5;
  --text-muted: #5e7d76;
  --border-color: #2a3f3b;
  --border-subtle: #1c2e2b;
  --accent: #2dd4bf;
  --accent-hover: #5eead4;
  --accent-soft: rgba(45, 212, 191, 0.08);
  --accent-soft-border: rgba(45, 212, 191, 0.18);
  --accent-gradient: linear-gradient(135deg, #2dd4bf, #38bdf8);
  --warm: #fbbf24;
  --warm-soft: rgba(251, 191, 36, 0.08);
  --warm-border: rgba(251, 191, 36, 0.18);
  --navbar-bg: rgba(12, 22, 21, 0.9);
  --card-shadow: 0 1px 4px rgba(0,0,0,0.35), 0 1px 2px rgba(0,0,0,0.2);
  --card-shadow-hover: 0 12px 28px rgba(0,0,0,0.45), 0 4px 10px rgba(0,0,0,0.25);
  --footer-bg: #070e0d;
  --footer-text: #5e7d76;
  --timeline-line: #2a3f3b;
  --timeline-dot: var(--accent);
  --hero-bg: linear-gradient(160deg, #142120 0%, #0c1615 50%, #1a1a0f 100%);
  --stats-bg: #0a1210;
  --stats-text: #5e7d76;
  --stats-number: #2dd4bf;
}

/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale; }
body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  transition: background 0.4s ease, color 0.4s ease;
}
a { color: var(--accent); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--accent-hover); }
img { max-width: 100%; height: auto; display: block; }
strong { font-weight: 600; }
.container { max-width: 1100px; margin: 0 auto; padding: 0 1.5rem; }

/* ===== Scroll Progress Bar ===== */
#progress-bar {
  position: fixed; top: 0; left: 0; height: 3px;
  background: var(--accent-gradient); width: 0%;
  z-index: 9999; transition: width 0.08s linear;
}

/* ===== Navbar ===== */
.navbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  background: var(--navbar-bg);
  backdrop-filter: blur(18px); -webkit-backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--border-color);
  padding: 0 2rem; height: 64px;
  display: flex; align-items: center; justify-content: space-between;
  transition: background 0.4s, border-color 0.4s, box-shadow 0.4s;
}
.navbar.scrolled { box-shadow: 0 2px 12px rgba(13, 148, 136, 0.06); }

.navbar-brand {
  font-weight: 800; font-size: 1.3rem;
  color: var(--text-primary); letter-spacing: -0.03em;
}
.navbar-brand span { color: var(--accent); }
.navbar-brand:hover { text-decoration: none; }

.navbar-nav {
  list-style: none; display: flex; gap: 0.2rem; align-items: center;
}
.navbar-nav a {
  color: var(--text-secondary); font-weight: 500; font-size: 0.88rem;
  padding: 0.4rem 0.8rem; border-radius: 8px;
  transition: all 0.2s;
}
.navbar-nav a:hover { color: var(--text-primary); background: var(--accent-soft); text-decoration: none; }
.navbar-nav a.active { color: var(--accent); background: var(--accent-soft); }

.navbar-controls { display: flex; align-items: center; gap: 0.5rem; }

.theme-toggle {
  background: var(--bg-tertiary); border: 1px solid var(--border-color);
  border-radius: 10px; padding: 0.45rem 0.6rem;
  cursor: pointer; font-size: 0.9rem;
  color: var(--text-secondary);
  transition: all 0.25s; display: flex; align-items: center;
}
.theme-toggle:hover { background: var(--accent-soft); border-color: var(--accent); color: var(--accent); }

.hamburger {
  display: none; background: none; border: 1px solid var(--border-color);
  border-radius: 10px; padding: 0.5rem; cursor: pointer;
  width: 40px; height: 40px;
  flex-direction: column; align-items: center; justify-content: center; gap: 4px;
}
.hamburger span {
  display: block; width: 18px; height: 2px;
  background: var(--text-secondary); border-radius: 2px;
  transition: all 0.3s;
}
.hamburger:hover { border-color: var(--accent); }
.hamburger:hover span { background: var(--accent); }

/* Mobile Menu */
.mobile-menu {
  display: none; position: fixed; top: 64px; left: 0; right: 0;
  background: var(--bg-primary); border-bottom: 1px solid var(--border-color);
  z-index: 999; padding: 0.75rem 1.5rem;
  box-shadow: 0 8px 24px rgba(0,0,0,0.08);
}
.mobile-menu.active { display: block; }
.mobile-menu ul { list-style: none; }
.mobile-menu li { border-bottom: 1px solid var(--border-subtle); }
.mobile-menu li:last-child { border-bottom: none; }
.mobile-menu a {
  display: block; padding: 0.75rem 0.5rem;
  color: var(--text-primary); font-weight: 500; font-size: 0.95rem;
}
.mobile-menu a:hover { color: var(--accent); text-decoration: none; }

/* ===== Section Layout ===== */
main { padding-top: 64px; }
section { padding: 5rem 0; }

.section-header { text-align: center; margin-bottom: 3rem; }
.section-tag {
  display: inline-block;
  font-family: 'JetBrains Mono', monospace; font-size: 0.78rem; font-weight: 500;
  letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--warm); background: var(--warm-soft);
  border: 1px solid var(--warm-border);
  padding: 0.3rem 0.85rem; border-radius: 6px;
  margin-bottom: 1rem;
}
.section-header h2 { font-size: 2.2rem; font-weight: 800; letter-spacing: -0.03em; margin-bottom: 0.6rem; }
.section-header p { color: var(--text-secondary); font-size: 1.05rem; max-width: 600px; margin: 0 auto; }
.section-header p a { color: var(--accent); }

/* ===== Hero ===== */
.hero {
  padding: 5rem 0 3rem;
  background: var(--hero-bg);
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute; bottom: -40%; left: -10%;
  width: 500px; height: 500px;
  background: radial-gradient(circle, rgba(13, 148, 136, 0.06) 0%, transparent 70%);
  border-radius: 50%; pointer-events: none;
}
.hero::after {
  content: '';
  position: absolute; top: -30%; right: -15%;
  width: 400px; height: 400px;
  background: radial-gradient(circle, rgba(217, 119, 6, 0.04) 0%, transparent 70%);
  border-radius: 50%; pointer-events: none;
}
.hero-inner {
  display: grid; grid-template-columns: 1fr 1fr; gap: 3rem;
  align-items: center; position: relative;
}
.hero-greeting {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.88rem; color: var(--warm); font-weight: 500;
  margin-bottom: 0.5rem;
  letter-spacing: 0.03em;
}
.hero-text h1 {
  font-size: clamp(2.4rem, 5vw, 3.4rem);
  font-weight: 800; letter-spacing: -0.04em;
  line-height: 1.1; margin-bottom: 0.75rem;
  color: var(--text-primary);
}
.hero-title {
  font-size: 1.1rem; font-weight: 600; color: var(--accent);
  margin-bottom: 0.25rem;
}
.hero-subtitle {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.85rem; color: var(--text-muted);
  margin-bottom: 1.5rem;
}
.hero-bio { color: var(--text-secondary); font-size: 0.98rem; margin-bottom: 1rem; line-height: 1.75; }
.hero-bio strong { color: var(--text-primary); }
.hero-cta { margin-top: 1.75rem; display: flex; flex-wrap: wrap; gap: 0.75rem; }

/* Hero Image */
.hero-image-col { text-align: center; }
.hero-avatar-wrap {
  width: 280px; height: 280px; margin: 0 auto;
  border-radius: 50%;
  background: conic-gradient(from 45deg, var(--accent), var(--warm), var(--accent));
  padding: 5px;
  box-shadow: 0 16px 48px rgba(13, 148, 136, 0.12);
  transition: transform 0.5s ease;
}
.hero-avatar-wrap:hover { transform: scale(1.03) rotate(3deg); }
.hero-avatar {
  width: 100%; height: 100%; border-radius: 50%; object-fit: cover;
  object-position: center 20%;
  background: var(--bg-card);
}
.hero-social {
  margin-top: 1.5rem; display: flex; justify-content: center;
  flex-wrap: wrap; gap: 0.5rem;
}
.hero-social a {
  width: 42px; height: 42px; border-radius: 50%;
  display: inline-flex; align-items: center; justify-content: center;
  background: var(--bg-card); color: var(--text-secondary);
  border: 1px solid var(--border-color);
  font-size: 1rem; transition: all 0.3s;
}
.hero-social a:hover {
  background: var(--accent); color: white;
  border-color: var(--accent); transform: translateY(-3px);
  box-shadow: 0 6px 16px rgba(13, 148, 136, 0.3);
  text-decoration: none;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex; align-items: center; gap: 0.5rem;
  padding: 0.7rem 1.4rem; border-radius: 10px;
  font-weight: 600; font-size: 0.92rem;
  border: none; cursor: pointer;
  transition: all 0.25s;
}
.btn-primary {
  background: var(--accent); color: #fff;
  box-shadow: 0 4px 14px rgba(13, 148, 136, 0.25);
}
.btn-primary:hover {
  background: var(--accent-hover);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(13, 148, 136, 0.35);
  color: #fff; text-decoration: none;
}
.btn-ghost {
  background: var(--accent-soft); color: var(--accent);
  border: 1px solid var(--accent-soft-border);
}
.btn-ghost:hover {
  background: var(--accent); color: #fff;
  border-color: var(--accent);
  transform: translateY(-2px); text-decoration: none;
}

/* ===== About Photo Section ===== */
.about-photo-section {
  padding: 3rem 0;
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
}
.about-photo-grid {
  display: grid; grid-template-columns: 280px 1fr; gap: 3rem;
  align-items: start;
}
.about-photo-wrap {
  border-radius: 16px; overflow: hidden;
  border: 3px solid var(--border-color);
  box-shadow: var(--card-shadow);
  transition: transform 0.3s;
}
.about-photo-wrap:hover { transform: scale(1.02); }
.about-photo { width: 100%; height: auto; display: block; }
.about-details h3 {
  font-size: 1.3rem; font-weight: 800; letter-spacing: -0.02em;
  margin-bottom: 1.25rem;
}
.about-info-grid {
  display: grid; grid-template-columns: 1fr 1fr; gap: 1rem;
}
.about-info-item {
  background: var(--bg-card); border: 1px solid var(--border-color);
  border-radius: 10px; padding: 1rem 1.15rem;
  box-shadow: var(--card-shadow);
}
.about-info-label {
  font-size: 0.78rem; font-weight: 600; color: var(--accent);
  text-transform: uppercase; letter-spacing: 0.05em;
  margin-bottom: 0.35rem;
}
.about-info-label i { margin-right: 0.3rem; }
.about-info-value {
  font-size: 0.88rem; color: var(--text-secondary); line-height: 1.55;
}

/* ===== Stats Bar ===== */
.stats-bar {
  background: var(--stats-bg);
  padding: 3.5rem 0;
  position: relative;
  overflow: hidden;
}
.stats-bar::before {
  content: '';
  position: absolute; inset: 0;
  background: repeating-linear-gradient(
    90deg,
    transparent, transparent 120px,
    rgba(255,255,255,0.02) 120px, rgba(255,255,255,0.02) 121px
  );
  pointer-events: none;
}
.stats-grid {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 2rem;
  text-align: center; position: relative;
}
.stat-item { position: relative; }
.stat-item + .stat-item::before {
  content: '';
  position: absolute; left: -1rem; top: 15%; height: 70%;
  width: 1px; background: rgba(255,255,255,0.08);
}
.stat-number {
  font-size: 2.6rem; font-weight: 800; letter-spacing: -0.04em;
  color: var(--stats-number);
  line-height: 1.2;
}
.stat-number::after { content: '+'; }
.stat-label { color: var(--stats-text); font-size: 0.88rem; font-weight: 500; margin-top: 0.3rem; }

/* ===== Research Cards ===== */
.research-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
}
.research-card {
  background: var(--bg-card); border: 1px solid var(--border-color);
  border-radius: 14px; padding: 1.75rem;
  box-shadow: var(--card-shadow);
  transition: all 0.3s ease;
  position: relative;
}
.research-card:hover {
  transform: translateY(-4px); box-shadow: var(--card-shadow-hover);
  border-color: var(--accent-soft-border);
}
.research-icon {
  width: 44px; height: 44px; border-radius: 10px;
  background: var(--accent-soft); color: var(--accent);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.1rem; margin-bottom: 1rem;
  border: 1px solid var(--accent-soft-border);
}
.research-card h3 { font-size: 1.05rem; font-weight: 700; margin-bottom: 0.5rem; letter-spacing: -0.01em; }
.research-card p { color: var(--text-secondary); font-size: 0.88rem; line-height: 1.65; }

/* ===== Publications ===== */
.publications-list { max-width: 850px; margin: 0 auto; }
.pub-item {
  display: flex; align-items: flex-start; gap: 1.25rem;
  padding: 1.25rem 1rem;
  border-bottom: 1px solid var(--border-subtle);
  border-radius: 10px;
  transition: all 0.2s;
}
.pub-item:last-child { border-bottom: none; }
.pub-item:hover { background: var(--accent-soft); }
.pub-year {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.82rem; font-weight: 500; color: var(--text-muted);
  min-width: 50px; padding-top: 0.15rem;
}
.pub-content { flex: 1; }
.pub-content h4 { font-size: 0.96rem; font-weight: 600; line-height: 1.45; margin-bottom: 0.3rem; letter-spacing: -0.01em; }
.pub-venue { color: var(--text-muted); font-size: 0.82rem; }
.pub-venue i { margin-right: 0.3rem; }
.pub-type {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.7rem; font-weight: 500;
  padding: 0.2rem 0.6rem; border-radius: 6px;
  white-space: nowrap; flex-shrink: 0; margin-top: 0.15rem;
}
.pub-type.journal { background: var(--accent-soft); color: var(--accent); border: 1px solid var(--accent-soft-border); }
.pub-type.conference { background: var(--warm-soft); color: var(--warm); border: 1px solid var(--warm-border); }

.pub-links { text-align: center; margin-top: 2rem; display: flex; flex-wrap: wrap; gap: 0.75rem; justify-content: center; }

/* ===== Timeline / Projects ===== */
.timeline { max-width: 800px; margin: 0 auto; position: relative; padding-left: 3rem; }
.timeline::before {
  content: ''; position: absolute; left: 11px; top: 0; bottom: 0;
  width: 2px; background: var(--timeline-line);
}
.timeline-item { position: relative; margin-bottom: 1.75rem; }
.timeline-item:last-child { margin-bottom: 0; }
.timeline-marker {
  position: absolute; left: -3rem; top: 1.5rem;
  width: 14px; height: 14px; border-radius: 50%;
  background: var(--warm); border: 3px solid var(--bg-primary);
  box-shadow: 0 0 0 3px var(--warm-soft);
  z-index: 1;
  transform: translateX(5px);
}
.timeline-card {
  background: var(--bg-card); border: 1px solid var(--border-color);
  border-radius: 12px; padding: 1.5rem;
  box-shadow: var(--card-shadow);
  transition: all 0.3s;
  border-left: 3px solid var(--warm);
}
.timeline-card:hover {
  box-shadow: var(--card-shadow-hover);
  transform: translateX(4px);
}
.timeline-date {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78rem; color: var(--warm); font-weight: 500;
  margin-bottom: 0.4rem;
}
.timeline-card h4 { font-size: 1.05rem; font-weight: 700; margin-bottom: 0.5rem; letter-spacing: -0.01em; }
.timeline-card p { color: var(--text-secondary); font-size: 0.88rem; line-height: 1.65; margin-bottom: 0.75rem; }
.project-funder {
  font-size: 0.8rem; color: var(--text-muted);
  display: inline-flex; align-items: center; gap: 0.4rem;
}

/* ===== Teaching Grid ===== */
.teaching-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
}
.teaching-card {
  background: var(--bg-card); border: 1px solid var(--border-color);
  border-radius: 14px; padding: 1.75rem;
  box-shadow: var(--card-shadow);
  transition: all 0.3s ease;
}
.teaching-card:hover {
  transform: translateY(-3px); box-shadow: var(--card-shadow-hover);
  border-color: var(--warm-border);
}
.teaching-icon {
  width: 44px; height: 44px; border-radius: 10px;
  background: var(--warm-soft); color: var(--warm);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.1rem; margin-bottom: 1rem;
  border: 1px solid var(--warm-border);
}
.teaching-card h3 { font-size: 1.05rem; font-weight: 700; margin-bottom: 0.5rem; }
.teaching-card p { color: var(--text-secondary); font-size: 0.88rem; line-height: 1.65; }

/* ===== Activities Grid ===== */
.activities-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1rem;
}
.activity-card {
  display: flex; align-items: flex-start; gap: 1rem;
  background: var(--bg-card); border: 1px solid var(--border-color);
  border-radius: 12px; padding: 1.25rem 1.5rem;
  box-shadow: var(--card-shadow);
  transition: all 0.3s;
}
.activity-card:hover {
  transform: translateY(-2px); box-shadow: var(--card-shadow-hover);
  border-color: var(--accent-soft-border);
}
.activity-icon {
  width: 40px; height: 40px; border-radius: 10px;
  background: var(--accent-soft); color: var(--accent);
  display: flex; align-items: center; justify-content: center;
  font-size: 0.95rem; flex-shrink: 0;
  border: 1px solid var(--accent-soft-border);
}
.activity-card h4 { font-size: 0.93rem; font-weight: 700; margin-bottom: 0.25rem; }
.activity-card p { color: var(--text-secondary); font-size: 0.84rem; line-height: 1.55; }

/* ===== Blog Grid ===== */
.blog-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
}
.blog-card {
  display: block;
  background: var(--bg-card); border: 1px solid var(--border-color);
  border-radius: 14px; padding: 1.75rem;
  box-shadow: var(--card-shadow);
  transition: all 0.3s; color: var(--text-primary);
  position: relative;
  overflow: hidden;
}
.blog-card::after {
  content: '';
  position: absolute; bottom: 0; left: 0; right: 0;
  height: 3px; background: linear-gradient(90deg, var(--accent), var(--warm));
  transform: scaleX(0); transform-origin: left;
  transition: transform 0.35s ease;
}
.blog-card:hover::after { transform: scaleX(1); }
.blog-card:hover {
  transform: translateY(-3px); box-shadow: var(--card-shadow-hover);
  text-decoration: none; color: var(--text-primary);
}
.blog-date {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78rem; color: var(--warm); font-weight: 500;
  margin-bottom: 0.6rem;
}
.blog-card h4 { font-size: 1.02rem; font-weight: 700; margin-bottom: 0.5rem; line-height: 1.35; letter-spacing: -0.01em; }
.blog-card p { color: var(--text-secondary); font-size: 0.86rem; line-height: 1.6; margin-bottom: 1rem; }
.blog-read {
  font-size: 0.84rem; font-weight: 600; color: var(--accent);
  display: inline-flex; align-items: center; gap: 0.35rem;
  transition: gap 0.2s;
}
.blog-card:hover .blog-read { gap: 0.65rem; }

.blog-cta { text-align: center; margin-top: 2rem; }

/* ===== Contact ===== */
#contact { padding: 4rem 0 5rem; }
.contact-card {
  text-align: center;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 20px;
  padding: 3.5rem 2rem;
  position: relative; overflow: hidden;
}
.contact-card::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0;
  height: 4px; background: linear-gradient(90deg, var(--accent), var(--warm), var(--accent));
}
.contact-card h2 { font-size: 2rem; font-weight: 800; letter-spacing: -0.03em; margin-bottom: 0.75rem; }
.contact-card > p { color: var(--text-secondary); max-width: 580px; margin: 0 auto 2rem; font-size: 1rem; line-height: 1.7; }
.contact-grid {
  display: flex; flex-wrap: wrap; justify-content: center; gap: 0.75rem;
}
.contact-item {
  display: inline-flex; align-items: center; gap: 0.6rem;
  background: var(--bg-card); border: 1px solid var(--border-color);
  padding: 0.7rem 1.2rem; border-radius: 10px;
  color: var(--text-primary); font-weight: 500; font-size: 0.9rem;
  transition: all 0.25s;
}
.contact-item i { color: var(--accent); font-size: 1rem; }
.contact-item:hover {
  border-color: var(--accent); background: var(--accent-soft);
  transform: translateY(-2px); text-decoration: none;
}

/* ===== Footer ===== */
footer {
  background: var(--footer-bg);
  color: var(--footer-text);
  padding: 2.5rem 1.5rem 2rem;
}
.footer-inner { text-align: center; }
.footer-brand { margin-bottom: 1.25rem; }
.footer-name { display: block; font-weight: 700; font-size: 1.05rem; color: #c8d9d5; }
.footer-title { display: block; font-size: 0.85rem; color: var(--footer-text); margin-top: 0.2rem; }
.footer-social { display: flex; justify-content: center; gap: 0.6rem; margin-bottom: 1.25rem; }
.footer-social a {
  width: 36px; height: 36px; border-radius: 50%;
  display: inline-flex; align-items: center; justify-content: center;
  color: var(--footer-text); background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.06);
  font-size: 0.9rem; transition: all 0.25s;
}
.footer-social a:hover {
  background: var(--accent); color: #fff;
  border-color: var(--accent); text-decoration: none;
  transform: translateY(-2px);
}
.footer-copyright { font-size: 0.82rem; }
.footer-copyright a { color: var(--accent); }

/* ===== Animations ===== */
[data-animate] {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}
[data-animate].visible {
  opacity: 1;
  transform: translateY(0);
}

/* ===== Responsive ===== */
@media (max-width: 900px) {
  .navbar-nav { display: none; }
  .hamburger { display: flex; }
  .hero-inner { grid-template-columns: 1fr; text-align: center; gap: 2.5rem; }
  .hero-text { order: 2; }
  .hero-image-col { order: 1; }
  .hero-cta { justify-content: center; }
  .hero-avatar-wrap { width: 220px; height: 220px; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 1.5rem; }
  .stat-item + .stat-item::before { display: none; }
  .hero { padding: 4rem 0 2rem; }
  .research-grid { grid-template-columns: repeat(2, 1fr); }
  .teaching-grid { grid-template-columns: 1fr; }
  .blog-grid { grid-template-columns: 1fr; }
  .about-photo-grid { grid-template-columns: 1fr; text-align: center; }
  .about-photo-wrap { max-width: 250px; margin: 0 auto; }
  .about-info-grid { grid-template-columns: 1fr; }
}

@media (max-width: 600px) {
  section { padding: 3.5rem 0; }
  .section-header h2 { font-size: 1.75rem; }
  .stat-number { font-size: 2rem; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 1rem; }
  .research-grid, .activities-grid {
    grid-template-columns: 1fr;
  }
  .pub-item { flex-direction: column; gap: 0.5rem; padding: 1rem 0.5rem; }
  .pub-type { align-self: flex-start; }
  .timeline { padding-left: 2rem; }
  .timeline-marker { left: -2rem; }
  .contact-card { padding: 2rem 1.25rem; }
  .contact-grid { flex-direction: column; align-items: center; }
  .navbar { padding: 0 1rem; }
}

@media (max-width: 400px) {
  .hero-avatar-wrap { width: 170px; height: 170px; }
  .hero-text h1 { font-size: 2rem; }
}