:root {
  --text: #222;
  --text-soft: #555;
  --muted: #888;
  --accent: #1E3A8A;
  --accent-hover: #3b5bb8;
  --bg: #ffffff;
  --bg-soft: #f7f8fa;
  --border: #e5e7eb;
  --max: 820px;
  --nav-h: 56px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen,
               Ubuntu, Cantarell, "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.15s ease, color 0.15s ease;
}
a:hover {
  color: var(--accent-hover);
  border-bottom-color: var(--accent-hover);
}

h1, h2, h3 { font-weight: 600; line-height: 1.25; }
h1 { font-size: 2.2rem; margin: 0 0 0.4rem; letter-spacing: -0.01em; }
h2 {
  font-size: 1.5rem;
  margin: 0 0 1.2rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--border);
  color: var(--text);
}
h3 { font-size: 1.1rem; margin: 1.8rem 0 0.8rem; color: var(--text-soft); }

p { margin: 0 0 1rem; }

/* --- top nav --- */
.topnav {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
  height: var(--nav-h);
}
.topnav-inner {
  max-width: var(--max);
  margin: 0 auto;
  height: 100%;
  padding: 0 1.2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.topnav .brand {
  font-weight: 600;
  color: var(--text);
  font-size: 1rem;
  letter-spacing: -0.01em;
  border: none;
}
.topnav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 1.25rem;
}
.topnav li a {
  color: var(--text-soft);
  font-size: 0.92rem;
  border: none;
}
.topnav li a:hover { color: var(--accent); }

/* --- hero --- */
.hero {
  padding: 3.5rem 1.2rem 2.5rem;
  background: var(--bg-soft);
  border-bottom: 1px solid var(--border);
}
.hero-inner {
  max-width: var(--max);
  margin: 0 auto;
  display: flex;
  gap: 2rem;
  align-items: center;
}
.hero-photo {
  width: 140px;
  height: 140px;
  object-fit: cover;
  border-radius: 50%;
  border: 3px solid #fff;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
  flex-shrink: 0;
}
.hero-text { flex: 1; min-width: 0; }
.tagline {
  font-size: 1.1rem;
  color: var(--text-soft);
  margin: 0 0 0.2rem;
}
.affil {
  font-size: 0.95rem;
  color: var(--text-soft);
  margin: 0 0 0.15rem;
}
.hero-links {
  margin-top: 1rem;
  font-size: 0.92rem;
  color: var(--muted);
}
.hero-links a {
  color: var(--accent);
  border-bottom: 1px solid transparent;
}
.hero-links a:hover { border-bottom-color: var(--accent-hover); }

/* --- main sections --- */
main {
  max-width: var(--max);
  margin: 0 auto;
  padding: 2.5rem 1.2rem 3rem;
}
section { margin-bottom: 3rem; scroll-margin-top: calc(var(--nav-h) + 10px); }

/* --- interests / awards lists --- */
.interests, .awards {
  list-style: none;
  padding: 0;
  margin: 0 0 1rem;
}
.interests li, .awards li {
  padding: 0.35rem 0 0.35rem 1.1rem;
  position: relative;
}
.interests li::before, .awards li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.85rem;
  width: 5px;
  height: 5px;
  background: var(--accent);
  border-radius: 50%;
}

/* --- publications --- */
.pubs {
  padding-left: 1.3rem;
  margin: 0;
}
.pubs li {
  margin-bottom: 1.1rem;
  line-height: 1.55;
}
.pub-title {
  font-weight: 500;
  color: var(--text);
}
.pub-authors { color: var(--text-soft); font-size: 0.95rem; }
.pub-venue { color: var(--muted); font-size: 0.92rem; font-style: italic; }

/* --- experience --- */
.exp {
  list-style: none;
  padding: 0;
  margin: 0;
}
.exp li {
  padding: 0.9rem 0;
  border-bottom: 1px solid var(--border);
}
.exp li:last-child { border-bottom: none; }
.exp-head {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.5rem;
  align-items: baseline;
  margin-bottom: 0.2rem;
}
.exp-date {
  color: var(--muted);
  font-size: 0.9rem;
  font-variant-numeric: tabular-nums;
}
.exp-desc {
  color: var(--text-soft);
  font-size: 0.95rem;
  line-height: 1.55;
}

/* --- contact --- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
}

/* --- footer --- */
footer {
  border-top: 1px solid var(--border);
  padding: 1.8rem 1.2rem;
  text-align: center;
  color: var(--muted);
  font-size: 0.88rem;
}

/* --- responsive --- */
@media (max-width: 640px) {
  h1 { font-size: 1.75rem; }
  h2 { font-size: 1.3rem; }
  .hero { padding: 2.5rem 1rem 2rem; }
  .hero-inner { flex-direction: column; align-items: flex-start; gap: 1.2rem; }
  .hero-photo { width: 110px; height: 110px; }
  .topnav ul { gap: 0.75rem; }
  .topnav li a { font-size: 0.82rem; }
  .topnav .brand { display: none; }
  .topnav-inner { justify-content: center; }
  .contact-grid { grid-template-columns: 1fr; }
}