/* ============================================
   Personal Academic Homepage — Global Styles
   ============================================ */

:root {
  --primary:    #2c3e50;
  --accent:     #2980b9;
  --accent-hover: #1a5f8a;
  --bg:         #f9f9f9;
  --surface:    #ffffff;
  --border:     #e0e0e0;
  --text:       #333333;
  --text-muted: #666666;
  --tag-bg:     #eaf3fb;
  --tag-color:  #2980b9;
  --nav-height: 60px;
  --max-width:  960px;
  --radius:     6px;
  --shadow:     0 2px 8px rgba(0,0,0,0.08);
  --transition: 0.2s ease;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
}

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

/* ── Navigation ─────────────────────────────── */
nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--primary);
  box-shadow: 0 2px 6px rgba(0,0,0,0.15);
}

nav .nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  height: var(--nav-height);
  padding: 0 24px;
  gap: 8px;
}

nav .nav-brand {
  font-size: 1.05rem;
  font-weight: 700;
  color: #fff;
  margin-right: auto;
  white-space: nowrap;
}

nav .nav-brand:hover { text-decoration: none; color: #cde; }

nav a.nav-link {
  color: rgba(255,255,255,0.82);
  font-size: 0.9rem;
  padding: 6px 14px;
  border-radius: var(--radius);
  transition: background var(--transition), color var(--transition);
}

nav a.nav-link:hover,
nav a.nav-link.active {
  background: rgba(255,255,255,0.15);
  color: #fff;
  text-decoration: none;
}

/* hamburger for mobile */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 4px;
  margin-left: auto;
}
.nav-toggle span {
  width: 24px; height: 2px;
  background: rgba(255,255,255,0.85);
  border-radius: 2px;
  transition: var(--transition);
}

/* ── Page wrapper ────────────────────────────── */
main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 40px 24px 80px;
}

/* ── Section headings ────────────────────────── */
.section-title {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--primary);
  border-left: 4px solid var(--accent);
  padding-left: 12px;
  margin: 40px 0 20px;
}

/* ── Profile / Hero ──────────────────────────── */
.profile-hero {
  display: flex;
  gap: 36px;
  align-items: flex-start;
  padding: 32px 0 16px;
}

.profile-photo {
  flex-shrink: 0;
  width: 160px;
  height: 160px;
  border-radius: 50%;
  object-fit: cover;
  border: 4px solid var(--border);
  background: #dde;
}

.profile-photo-placeholder {
  flex-shrink: 0;
  width: 160px;
  height: 160px;
  border-radius: 50%;
  border: 4px solid var(--border);
  background: linear-gradient(135deg, #b8cfe8, #d0e4f5);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3.5rem;
  color: var(--accent);
  font-weight: 300;
}

.profile-info h1 {
  font-size: 2rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 4px;
}

.profile-info .title {
  font-size: 1rem;
  color: var(--text-muted);
  margin-bottom: 2px;
}

.profile-info .affiliation {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 16px;
}

.contact-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 12px;
}

.contact-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.85rem;
  color: var(--accent);
  border: 1px solid var(--accent);
  padding: 4px 12px;
  border-radius: 20px;
  transition: background var(--transition), color var(--transition);
}

.contact-link:hover {
  background: var(--accent);
  color: #fff;
  text-decoration: none;
}

.contact-link svg { width: 14px; height: 14px; }

/* ── Bio ─────────────────────────────────────── */
.bio p { margin-bottom: 12px; color: var(--text); }

/* ── News ────────────────────────────────────── */
.news-list { list-style: none; }

.news-list li {
  display: flex;
  gap: 16px;
  padding: 10px 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.92rem;
}

.news-list li:last-child { border-bottom: none; }

.news-date {
  flex-shrink: 0;
  width: 108px;
  color: var(--text-muted);
  font-size: 0.85rem;
  padding-top: 2px;
}

.news-badge {
  flex-shrink: 0;
  font-size: 0.72rem;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: 12px;
  align-self: flex-start;
  margin-top: 3px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.badge-paper   { background: #d4edda; color: #155724; }
.badge-award   { background: #fff3cd; color: #856404; }
.badge-talk    { background: #cce5ff; color: #004085; }
.badge-service { background: #f8d7da; color: #721c24; }
.badge-misc    { background: #e2e3e5; color: #383d41; }

/* ── Interest tags ───────────────────────────── */
.interest-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 16px;
}

.interest-tag {
  font-size: 0.85rem;
  padding: 4px 14px;
  border-radius: 20px;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text);
}

/* ── Publications ────────────────────────────── */
.pub-list { list-style: none; }

.pub-item {
  display: flex;
  gap: 16px;
  padding: 16px 0;
  border-bottom: 1px solid var(--border);
}

.pub-item:last-child { border-bottom: none; }

.pub-thumb {
  flex-shrink: 0;
  width: 100px;
  height: 75px;
  background: linear-gradient(135deg, #e8eef5, #d0dce8);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.8rem;
  color: var(--accent);
  overflow: hidden;
}

.pub-thumb img { width: 100%; height: 100%; object-fit: cover; border-radius: var(--radius); }

.pub-content { flex: 1; }

.pub-title {
  font-size: 0.97rem;
  font-weight: 600;
  color: var(--primary);
  margin-bottom: 4px;
}

.pub-title a { color: var(--primary); }
.pub-title a:hover { color: var(--accent); }

.pub-authors {
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-bottom: 2px;
}

.pub-authors .author-me { font-weight: 700; color: var(--text); text-decoration: underline dotted; }

.pub-venue {
  font-size: 0.87rem;
  font-style: italic;
  color: var(--text-muted);
  margin-bottom: 8px;
}

.pub-links {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.pub-link {
  font-size: 0.78rem;
  padding: 2px 10px;
  border-radius: 12px;
  border: 1px solid var(--accent);
  color: var(--accent);
  transition: background var(--transition), color var(--transition);
}

.pub-link:hover {
  background: var(--accent);
  color: #fff;
  text-decoration: none;
}

.pub-tag {
  font-size: 0.75rem;
  padding: 2px 8px;
  border-radius: 12px;
  background: var(--tag-bg);
  color: var(--tag-color);
  font-weight: 700;
}

.pub-tag.oral     { background: #fdecea; color: #c0392b; }
.pub-tag.best     { background: #fdf6e3; color: #b8860b; }
.pub-tag.accepted { background: #d4edda; color: #155724; }
.pub-tag.review   { background: #fff3cd; color: #856404; }
.pub-tag.preprint { background: #f3e5f5; color: #6a1b9a; }
.pub-tag.q1       { background: #d1ecf1; color: #0c5460; }
.pub-tag.q2       { background: #e2e3e5; color: #383d41; }
.pub-tag.ccfa     { background: #cfe2ff; color: #084298; font-weight: 700; }
.pub-tag.ccfb     { background: #dce8ff; color: #1a56a0; font-weight: 700; }
.pub-tag.ei       { background: #e8d5f5; color: #5a189a; }
.pub-tag.venue    { background: #e8f4f8; color: #0969da; }

.pub-tags { display: flex; flex-wrap: wrap; gap: 4px; margin-top: 4px; }

.pub-cited {
  display: inline-flex;
  align-items: center;
  gap: 3px;
  font-size: 0.76rem;
  color: var(--text-muted);
  margin-left: 4px;
}
.pub-cited::before { content: "Cited by "; }

/* ── Publication filter bar ─────────────────── */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 24px;
}

.filter-btn {
  padding: 5px 16px;
  border-radius: 20px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-muted);
  font-size: 0.85rem;
  cursor: pointer;
  transition: all var(--transition);
}

.filter-btn:hover,
.filter-btn.active {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

/* ── Projects ────────────────────────────────── */
.project-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 20px;
}

.project-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  transition: transform var(--transition), box-shadow var(--transition);
}

.project-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 6px 18px rgba(0,0,0,0.12);
}

.project-img {
  width: 100%;
  height: 150px;
  object-fit: cover;
  background: linear-gradient(135deg, #e0eaf5, #c5d9ef);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.5rem;
  color: var(--accent);
}

.project-body { padding: 16px; }

.project-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 6px;
}

.project-desc {
  font-size: 0.87rem;
  color: var(--text-muted);
  margin-bottom: 12px;
}

.project-tags { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 12px; }

.project-tag {
  font-size: 0.75rem;
  padding: 2px 8px;
  background: var(--tag-bg);
  color: var(--tag-color);
  border-radius: 12px;
}

.project-links { display: flex; gap: 8px; }

.btn {
  display: inline-block;
  padding: 5px 14px;
  border-radius: 20px;
  font-size: 0.82rem;
  font-weight: 600;
  border: 1px solid var(--accent);
  color: var(--accent);
  transition: all var(--transition);
  cursor: pointer;
}

.btn:hover { background: var(--accent); color: #fff; text-decoration: none; }
.btn.btn-solid { background: var(--accent); color: #fff; }
.btn.btn-solid:hover { background: var(--accent-hover); }

/* ── CV Page ─────────────────────────────────── */
.cv-section { margin-bottom: 32px; }

.cv-item {
  display: flex;
  gap: 20px;
  padding: 10px 0;
  border-bottom: 1px dashed var(--border);
}

.cv-item:last-child { border-bottom: none; }

.cv-date {
  flex-shrink: 0;
  width: 130px;
  font-size: 0.85rem;
  color: var(--text-muted);
  padding-top: 2px;
}

.cv-content .cv-title { font-weight: 600; color: var(--primary); }
.cv-content .cv-subtitle { font-size: 0.9rem; color: var(--text-muted); }
.cv-content .cv-detail  { font-size: 0.87rem; color: var(--text); margin-top: 4px; }

.cv-download-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 24px;
  background: var(--accent);
  color: #fff;
  border-radius: var(--radius);
  font-weight: 600;
  margin-bottom: 32px;
  transition: background var(--transition);
}

.cv-download-btn:hover { background: var(--accent-hover); color: #fff; text-decoration: none; }

/* ── Gallery ─────────────────────────────────── */
.gallery-grid {
  columns: 3;
  column-gap: 16px;
}

.gallery-item {
  break-inside: avoid;
  margin-bottom: 16px;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
  background: var(--surface);
  box-shadow: var(--shadow);
  cursor: pointer;
  transition: transform var(--transition), box-shadow var(--transition);
}

.gallery-item:hover { transform: scale(1.02); box-shadow: 0 4px 16px rgba(0,0,0,0.14); }

.gallery-item img {
  width: 100%;
  display: block;
}

.gallery-placeholder {
  width: 100%;
  aspect-ratio: 4/3;
  background: linear-gradient(135deg, #e0eaf5, #c5d9ef);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.5rem;
  color: var(--accent);
}

.gallery-caption {
  padding: 8px 12px;
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* Lightbox */
.lightbox {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.88);
  z-index: 999;
  align-items: center;
  justify-content: center;
}

.lightbox.open { display: flex; }

.lightbox img {
  max-width: 90vw;
  max-height: 85vh;
  border-radius: var(--radius);
  box-shadow: 0 8px 32px rgba(0,0,0,0.4);
}

.lightbox-close {
  position: absolute;
  top: 20px;
  right: 28px;
  color: #fff;
  font-size: 2rem;
  cursor: pointer;
  line-height: 1;
  opacity: 0.8;
}

.lightbox-close:hover { opacity: 1; }

/* ── Footer ──────────────────────────────────── */
footer {
  text-align: center;
  padding: 24px;
  font-size: 0.82rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border);
  margin-top: 60px;
}

/* ── Utilities ───────────────────────────────── */
.divider { border: none; border-top: 1px solid var(--border); margin: 32px 0; }

.show-more-btn {
  display: block;
  margin: 20px auto 0;
  padding: 8px 28px;
  border: 1px solid var(--border);
  border-radius: 20px;
  background: var(--surface);
  color: var(--text-muted);
  font-size: 0.9rem;
  cursor: pointer;
  transition: all var(--transition);
}

.show-more-btn:hover { border-color: var(--accent); color: var(--accent); }

.news-list.expanded {
  max-height: 340px;
  overflow-y: auto;
  padding-right: 6px;
  scroll-behavior: smooth;
}

/* ── Responsive ──────────────────────────────── */
@media (max-width: 680px) {
  .nav-links { display: none; flex-direction: column; width: 100%; padding: 12px 0; }
  .nav-links.open { display: flex; }
  nav .nav-inner { flex-wrap: wrap; height: auto; padding: 12px 16px; }
  .nav-toggle { display: flex; }

  .profile-hero { flex-direction: column; align-items: center; text-align: center; }
  .contact-links { justify-content: center; }

  .pub-item { flex-direction: column; }
  .pub-thumb { width: 100%; height: 160px; }

  .cv-item { flex-direction: column; gap: 4px; }
  .cv-date { width: auto; }

  .gallery-grid { columns: 2; }

  main { padding: 24px 16px 60px; }
}

@media (max-width: 400px) {
  .gallery-grid { columns: 1; }
  .project-grid { grid-template-columns: 1fr; }
}