/* ---------- Base ---------- */
:root {
  --bg: #ffffff;
  --bg-alt: #f6f8fa;
  --text: #1f2937;
  --muted: #6b7280;
  --border: #e5e7eb;
  --accent: #2563eb;
  --accent-dark: #1d4ed8;
  --maxw: 820px;
  --nav-h: 60px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.65;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.15s ease;
}
a:hover { color: var(--accent-dark); }

h1, h2, h3 { line-height: 1.25; font-weight: 700; letter-spacing: -0.01em; }
h2 {
  font-size: 1.5rem;
  margin: 0 0 1.25rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--border);
}
h3 { font-size: 1.05rem; margin: 0 0 0.4rem; }

/* ---------- Top nav ---------- */
.topnav {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-h);
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(180%) blur(8px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  max-width: var(--maxw);
  height: 100%;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.brand {
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--text);
}
.brand:hover { color: var(--accent); }
.nav-links { display: flex; gap: 28px; }
.nav-links a {
  color: var(--muted);
  font-size: 0.95rem;
  font-weight: 500;
  padding: 4px 0;
  border-bottom: 2px solid transparent;
}
.nav-links a:hover,
.nav-links a.active { color: var(--text); border-bottom-color: var(--accent); }
.nav-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.4rem;
  cursor: pointer;
  color: var(--text);
  line-height: 1;
}

/* ---------- Sections ---------- */
main { display: block; }
.section {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 64px 24px;
  scroll-margin-top: var(--nav-h);
}
.section.alt {
  max-width: none;
  background: var(--bg-alt);
}
.section.alt > * { max-width: var(--maxw); margin-left: auto; margin-right: auto; }

/* ---------- Profile ---------- */
.profile { text-align: center; padding-top: 72px; }
.profile-photo {
  width: 168px;
  height: 168px;
  object-fit: cover;
  border-radius: 50%;
  border: 1px solid var(--border);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.06);
}
.profile h1 { font-size: 2rem; margin: 1rem 0 0.25rem; }
.tagline { color: var(--muted); margin: 0 0 1.5rem; font-size: 1.02rem; }
.bio {
  text-align: justify;
  max-width: 680px;
  margin: 0 auto 1rem;
  color: #374151;
}
.contact { margin: 0.5rem 0; }
.links { margin-top: 0.75rem; }
.links .sep { color: var(--border); margin: 0 6px; }

/* ---------- News / Awards lists ---------- */
.news-list, .awards-list {
  list-style: none;
  margin: 0;
  padding: 0;
}
.news-list li, .awards-list li {
  display: flex;
  gap: 16px;
  padding: 10px 0;
  border-bottom: 1px solid var(--border);
  align-items: baseline;
}
.news-list li:last-child, .awards-list li:last-child { border-bottom: none; }
.date {
  flex: 0 0 84px;
  font-weight: 600;
  color: var(--accent);
  font-variant-numeric: tabular-nums;
  font-size: 0.92rem;
}
.item-text { color: #374151; }

/* ---------- Education cards ---------- */
.cards { display: flex; flex-direction: column; gap: 16px; }
.edu-card {
  display: flex;
  gap: 20px;
  padding: 20px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 10px;
}
.edu-logo {
  flex: 0 0 64px;
  width: 64px;
  height: 64px;
  object-fit: contain;
}
.edu-inst { font-weight: 700; font-size: 1.02rem; }
.edu-period { color: var(--muted); font-size: 0.9rem; margin: 2px 0 6px; }
.exp-role { color: var(--accent-dark, #1d4ed8); font-weight: 600; font-size: 0.92rem; }
.edu-details { margin: 0; padding-left: 18px; }
.edu-details li { margin: 2px 0; color: #374151; }
.edu-details li.note { color: var(--muted); font-style: italic; list-style: none; margin-left: -18px; }

/* ---------- Publications ---------- */
.pub-subhead {
  font-size: 1.15rem;
  margin: 2rem 0 1rem;
  color: var(--text);
}
.pub {
  display: flex;
  gap: 22px;
  padding: 20px;
  margin-bottom: 16px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  transition: box-shadow 0.18s ease, transform 0.18s ease;
}
.pub:hover { box-shadow: 0 6px 20px rgba(0, 0, 0, 0.07); transform: translateY(-1px); }
.pub-thumb {
  flex: 0 0 150px;
  width: 150px;
  height: 100px;
  background: var(--bg-alt);
  border-radius: 8px;
  overflow: hidden;
  cursor: zoom-in;
}
.pub-thumb img { width: 100%; height: 100%; object-fit: cover; display: block; }
.pub-thumb.no-img img { display: none; }
.pub-body { min-width: 0; }
.pub-title { font-size: 1.05rem; }
.pub-authors { font-size: 0.92rem; color: #4b5563; margin: 0 0 4px; }
.author-note { color: var(--muted); font-size: 0.85rem; }
.pub-venue { font-size: 0.92rem; color: #4b5563; margin: 0 0 6px; }
.pub-links { margin: 0 0 4px; }
.pub-links a { font-weight: 600; }
.soon { color: var(--muted); }
.pub-keywords { font-size: 0.85rem; color: var(--muted); margin: 4px 0 0; }

/* ---------- Custom text section ---------- */
.text-block { max-width: 680px; margin: 0 auto; }
.text-block p { text-align: justify; margin: 0 0 1rem; color: #374151; }

/* ---------- Hover preview popover ---------- */
#pub-preview {
  position: fixed;
  z-index: 200;
  max-width: 360px;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.12s ease;
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.18);
  border: 1px solid var(--border);
  background: var(--bg);
}
#pub-preview.show { opacity: 1; }
#pub-preview img { display: block; width: 360px; max-width: 100%; height: auto; }

/* ---------- Footer ---------- */
.footer {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 32px 24px 48px;
  text-align: center;
  color: var(--muted);
  font-size: 0.88rem;
}
.footer .attr { margin-top: 4px; }

/* ---------- Responsive ---------- */
@media (max-width: 700px) {
  .nav-toggle { display: block; }
  .nav-links {
    position: absolute;
    top: var(--nav-h);
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    padding: 8px 24px;
    display: none;
  }
  .nav-links.open { display: flex; }
  .nav-links a { padding: 10px 0; border-bottom: none; }

  .section { padding: 44px 20px; }
  .profile { padding-top: 48px; }
  .profile-photo { width: 130px; height: 130px; }
  .profile h1 { font-size: 1.6rem; }

  .pub { flex-direction: column; gap: 14px; }
  .pub-thumb { flex: none; width: 100%; height: 150px; }

  .date { flex: 0 0 70px; }
}