/* ===== Design tokens: Navy & Slate ===== */
:root {
  --bg: #f5f6f7;
  --surface: #ffffff;
  --border: #dde1e4;
  --text: #1b222c;
  --text-muted: #5f6670;
  --text-faint: #8b929b;
  --accent: #1c3a5e;
  --accent-dark: #142a44;
  --accent-tint: #e4e9ee;
  --link: #1a56db;
  --link-hover: #123f9e;
  --shadow: none;
  --shadow-md: none;
  --radius: 4px;
  --max-width: 880px;
  --font-ui: 'IBM Plex Sans', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-display: 'Source Serif 4', Georgia, 'Times New Roman', serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-ui);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--link); text-decoration: none; }
a:hover { color: var(--link-hover); text-decoration: underline; }

img { max-width: 100%; display: block; }

.wrap {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

/* ===== Header / Nav ===== */
header.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.1rem;
  color: var(--text);
  letter-spacing: -0.01em;
}
.brand:hover { color: var(--text); text-decoration: none; }

nav.site-nav ul {
  list-style: none;
  display: flex;
  gap: 4px;
  margin: 0;
  padding: 0;
}

nav.site-nav a {
  color: var(--text-muted);
  font-size: 0.92rem;
  font-weight: 500;
  padding: 8px 2px;
  margin: 0 10px;
  border-bottom: 2px solid transparent;
  display: inline-block;
}

nav.site-nav a:hover {
  color: var(--text);
  text-decoration: none;
  border-bottom-color: var(--border);
}

nav.site-nav a.active {
  color: var(--text);
  border-bottom-color: var(--accent);
}

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 7px 10px;
  color: var(--text);
  font-size: 1rem;
  cursor: pointer;
}

@media (max-width: 640px) {
  .nav-toggle { display: block; }
  nav.site-nav {
    display: none;
    width: 100%;
  }
  nav.site-nav.open { display: block; }
  nav.site-nav ul {
    flex-direction: column;
    gap: 2px;
    padding: 8px 0 14px;
  }
  nav.site-nav a {
    margin: 0;
    border-bottom: none;
    border-left: 2px solid transparent;
    padding: 8px 12px;
  }
  nav.site-nav a:hover { border-left-color: var(--border); }
  nav.site-nav a.active { border-left-color: var(--accent); }
  .nav-inner { flex-wrap: wrap; }
}

/* ===== Hero ===== */
.hero {
  padding: 56px 0 32px;
  border-bottom: 1px solid var(--border);
}

.hero-grid {
  display: flex;
  align-items: center;
  gap: 36px;
}

.avatar {
  width: 152px;
  height: 152px;
  border-radius: 50%;
  object-fit: cover;
  border: 1px solid var(--border);
  flex-shrink: 0;
}

.avatar-fallback {
  width: 128px;
  height: 128px;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.2rem;
  font-weight: 700;
  flex-shrink: 0;
  box-shadow: var(--shadow-md);
}

.hero h1 {
  font-family: var(--font-display);
  font-weight: 600;
  margin: 0 0 6px;
  font-size: 2.1rem;
  letter-spacing: -0.01em;
}

.hero .role {
  margin: 0 0 10px;
  color: var(--text-muted);
  font-size: 1.08rem;
  font-weight: 500;
}

@media (max-width: 560px) {
  .hero-grid { flex-direction: column; text-align: center; align-items: center; }
}

/* ===== Bio ===== */
.bio-text p {
  color: #4e5560;
  font-size: 1rem;
  line-height: 1.75;
  max-width: 68ch;
  margin: 0 0 18px;
  text-align: justify;
}
.bio-text p:last-child { margin-bottom: 0; }

.interests {
  margin: 26px 0 0;
  padding-top: 20px;
  border-top: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.92rem;
  max-width: 68ch;
}
.interests-label {
  display: block;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 6px;
}

.more-links {
  margin: 20px 0 0;
  color: var(--text-muted);
  font-size: 0.95rem;
  max-width: 68ch;
}

/* ===== Section / cards ===== */
.section { padding: 28px 0; }
.section h2 {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.35rem;
  letter-spacing: -0.01em;
  margin-bottom: 18px;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 22px;
  box-shadow: var(--shadow);
}

.card + .card { margin-top: 14px; }

/* ===== Timeline (CV) ===== */
.timeline-item {
  border-left: 2px solid var(--border);
  padding: 2px 0 24px 22px;
  position: relative;
}
.timeline-item::before {
  content: "";
  position: absolute;
  left: -6px;
  top: 4px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--accent);
}
.timeline-item:last-child { padding-bottom: 2px; }

.timeline-item h3 {
  font-family: var(--font-display);
  font-weight: 600;
  margin: 0 0 2px;
  font-size: 1.05rem;
}
.timeline-item .org {
  color: var(--accent-dark);
  font-weight: 600;
  font-size: 0.92rem;
}
.timeline-item .meta {
  color: var(--text-faint);
  font-size: 0.82rem;
  margin: 2px 0 8px;
}
.timeline-item ul {
  margin: 6px 0 0;
  padding-left: 18px;
  color: var(--text-muted);
  font-size: 0.92rem;
}
.timeline-item p {
  color: var(--text-muted);
  font-size: 0.92rem;
  margin: 6px 0 0;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--accent);
  color: #fff;
  font-weight: 600;
  font-size: 0.9rem;
  padding: 10px 18px;
  border-radius: 8px;
  box-shadow: var(--shadow);
}
.btn:hover { background: var(--accent-dark); color: #fff; text-decoration: none; }

.btn-outline {
  background: transparent;
  color: var(--accent-dark);
  border: 1px solid var(--accent);
}
.btn-outline:hover { background: var(--accent-tint); color: var(--accent-dark); }

/* ===== Research cards ===== */
.paper .paper-title {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 600;
  margin: 0 0 4px;
}
.paper .paper-meta {
  color: var(--text-faint);
  font-size: 0.85rem;
  margin: 0 0 10px;
}
.paper .status {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  color: var(--accent-dark);
  background: var(--accent-tint);
  padding: 3px 9px;
  border-radius: 999px;
  margin-bottom: 10px;
}
.paper p { color: var(--text-muted); margin: 0 0 10px; font-size: 0.95rem; }

/* ===== Teaching ===== */
.lecture-list {
  list-style: none;
  margin: 0;
  padding: 0;
}
.lecture-item {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 0;
  border-bottom: 1px solid var(--border);
}
.lecture-item:last-child { border-bottom: none; }
.lecture-num {
  font-family: var(--font-display);
  color: var(--accent);
  font-weight: 600;
  font-size: 0.85rem;
  flex-shrink: 0;
  width: 70px;
}
.lecture-body { flex: 1; min-width: 0; }
.lecture-title { font-weight: 600; font-size: 0.95rem; margin: 0 0 2px; }
.lecture-topics { color: var(--text-faint); font-size: 0.82rem; margin: 0; }
.lecture-dl {
  flex-shrink: 0;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--accent);
  padding: 6px 12px;
  border: 1px solid var(--border);
  border-radius: 7px;
}
.lecture-dl:hover { background: var(--accent-tint); text-decoration: none; }

/* ===== Resource lists ===== */
.resource-list {
  list-style: none;
  margin: 0;
  padding: 0;
}
.resource-list li {
  padding: 10px 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.95rem;
}
.resource-list li:last-child { border-bottom: none; }
.resource-list a { font-weight: 600; }
.resource-list .url {
  display: block;
  color: var(--text-faint);
  font-size: 0.8rem;
  margin-top: 2px;
}

/* ===== Contact ===== */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 14px;
}
.contact-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
  box-shadow: var(--shadow);
  display: flex;
  align-items: center;
  gap: 12px;
}
.contact-card .icon {
  width: 38px;
  height: 38px;
  border-radius: 10px;
  background: var(--accent-tint);
  color: var(--accent-dark);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  flex-shrink: 0;
}
.contact-card .contact-name {
  font-weight: 600;
  font-size: 0.95rem;
  min-width: 0;
}

/* ===== Footer ===== */
footer.site-footer {
  border-top: 1px solid var(--border);
  margin-top: 40px;
  padding: 24px 0 48px;
  color: var(--text-faint);
  font-size: 0.85rem;
  text-align: center;
}
footer.site-footer a { color: var(--text-muted); }