/* =========================================================
   Academic Homepage — Design System
   ========================================================= */

/* Design Tokens */
:root {
  --bg:           #fdfcfa;
  --surface:      #ffffff;
  --surface-2:    #f9f7f3;
  --border:       #ece8e0;
  --text:         #2c2826;
  --text-muted:   #7a6f64;
  --accent:       #8b6f47;
  --accent-light: #f6f1ea;
  --accent-hover: #6d5535;
  --radius:       8px;
  --radius-sm:    4px;
  --shadow-sm:    0 1px 3px rgba(44,40,38,0.08);
  --shadow-md:    0 3px 8px rgba(44,40,38,0.10);
}

/* Reset & Base */
*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: 'Georgia', 'Times New Roman', serif;
  font-size: 15px;
  line-height: 1.65;
  padding-top: 52px; /* offset for fixed navbar */
}

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

/* =========================================================
   Navbar
   ========================================================= */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: 52px;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  z-index: 100;
  display: flex;
  align-items: center;
  padding: 0 24px;
}

.navbar-inner {
  max-width: 910px;
  width: 100%;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.navbar-brand {
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
  letter-spacing: 0.01em;
}
.navbar-brand:hover { color: var(--accent); text-decoration: none; }

.navbar-links {
  display: flex;
  align-items: center;
  gap: 4px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.navbar-links a {
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 13px;
  color: var(--text-muted);
  padding: 5px 10px;
  border-radius: var(--radius-sm);
  transition: color 0.15s, background 0.15s;
}
.navbar-links a:hover,
.navbar-links a.active {
  color: var(--accent);
  background: var(--accent-light);
  text-decoration: none;
}

/* =========================================================
   Page Container
   ========================================================= */
.container {
  max-width: 910px;
  margin: 0 auto;
  padding: 40px 24px 80px;
}

/* =========================================================
   Hero Section
   ========================================================= */
.hero {
  display: flex;
  align-items: flex-start;
  gap: 32px;
  margin-bottom: 48px;
  padding-bottom: 40px;
  border-bottom: 1px solid var(--border);
}

.hero-photo {
  flex-shrink: 0;
  width: 148px;
  height: 148px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid var(--border);
}

.hero-info { flex: 1; }

.hero-name {
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 26px;
  font-weight: 700;
  color: var(--text);
  margin: 0 0 6px;
  line-height: 1.2;
}

.hero-affil {
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.6;
  margin: 0 0 14px;
}
.hero-affil a { color: var(--text-muted); }
.hero-affil a:hover { color: var(--accent); text-decoration: underline; }

.hero-location {
  font-size: 13px;
  color: var(--text-muted);
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 5px;
}

.hero-social {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.social-link {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 12px;
  color: var(--text-muted);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 4px 10px;
  transition: color 0.15s, border-color 0.15s, background 0.15s;
  text-decoration: none;
}
.social-link:hover {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-light);
  text-decoration: none;
}
.social-link svg { flex-shrink: 0; }

/* =========================================================
   Section
   ========================================================= */
.section {
  margin-bottom: 48px;
}

.section-title {
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.10em;
  text-transform: uppercase;
  color: var(--text-muted);
  border-bottom: 1px solid var(--border);
  padding-bottom: 8px;
  margin: 0 0 20px;
}

/* =========================================================
   News
   ========================================================= */
.news-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.news-item {
  display: flex;
  align-items: baseline;
  gap: 10px;
  font-size: 14px;
  line-height: 1.55;
}

.news-date {
  flex-shrink: 0;
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 11px;
  font-weight: 600;
  background: var(--accent-light);
  color: var(--accent);
  border-radius: 3px;
  padding: 2px 7px;
  white-space: nowrap;
}

/* =========================================================
   Publication Cards
   ========================================================= */
.pub-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.pub-card {
  display: flex;
  gap: 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  transition: box-shadow 0.18s;
}
.pub-card:hover {
  box-shadow: var(--shadow-md);
}

.pub-img {
  flex-shrink: 0;
  width: 190px;
  height: 120px;
  object-fit: contain;
  background: var(--surface);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
}

.pub-body { flex: 1; min-width: 0; }

.pub-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
  line-height: 1.45;
  margin: 0 0 6px;
}
.pub-title a { color: var(--text); }
.pub-title a:hover { color: var(--accent); text-decoration: none; }

.pub-authors {
  font-size: 13px;
  color: var(--text-muted);
  margin: 0 0 4px;
}

.pub-venue {
  font-size: 13px;
  color: var(--text-muted);
  font-style: italic;
  margin: 0 0 8px;
}
.pub-venue strong { font-style: normal; }

.pub-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  margin-bottom: 8px;
}

.badge {
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 11px;
  font-weight: 600;
  background: var(--accent-light);
  color: var(--accent);
  border-radius: 3px;
  padding: 2px 6px;
}
.badge-hot {
  background: #fef3e2;
  color: #b45309;
}

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

.pub-link {
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 12px;
  color: var(--text-muted);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 2px 8px;
  transition: color 0.15s, border-color 0.15s, background 0.15s;
  text-decoration: none;
}
.pub-link:hover {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-light);
  text-decoration: none;
}

/* Category label inside publication pages */
.pub-category {
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin: 28px 0 12px;
}
.pub-category:first-child { margin-top: 0; }

/* CTA link */
.view-all-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 13px;
  color: var(--accent);
  margin-top: 16px;
  text-decoration: none;
  font-weight: 500;
}
.view-all-link:hover { color: var(--accent-hover); text-decoration: underline; }

/* =========================================================
   Collapsible sections (<details>)
   ========================================================= */
.collapsible {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 10px;
  overflow: hidden;
}

.collapsible summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 13px 18px;
  cursor: pointer;
  background: var(--surface-2);
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-muted);
  user-select: none;
  list-style: none;
  transition: background 0.15s;
}
.collapsible summary::-webkit-details-marker { display: none; }
.collapsible summary::after {
  content: '';
  display: inline-block;
  width: 8px;
  height: 8px;
  border-right: 2px solid var(--text-muted);
  border-bottom: 2px solid var(--text-muted);
  transform: rotate(45deg);
  transition: transform 0.2s;
  margin-top: -3px;
}
.collapsible[open] summary::after {
  transform: rotate(-135deg);
  margin-top: 3px;
}
.collapsible summary:hover { background: var(--border); }

.collapsible-body {
  padding: 16px 20px 18px;
  background: var(--surface);
  font-size: 14px;
}

.collapsible-body ul {
  margin: 0;
  padding-left: 18px;
}
.collapsible-body li {
  margin-bottom: 5px;
  line-height: 1.55;
}
.collapsible-body p { margin: 0 0 8px; font-weight: 600; }

/* =========================================================
   Experience sub-items
   ========================================================= */
.exp-row {
  display: flex;
  gap: 16px;
  font-size: 14px;
  line-height: 1.5;
  margin-bottom: 7px;
}
.exp-date {
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 12px;
  color: var(--text-muted);
  white-space: nowrap;
  min-width: 110px;
  padding-top: 1px;
}

/* =========================================================
   Life page grid
   ========================================================= */
.life-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 12px;
  margin-top: 12px;
}

.life-placeholder {
  background: var(--surface-2);
  border: 1px dashed var(--border);
  border-radius: var(--radius);
  height: 140px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 12px;
  color: var(--text-muted);
}

.life-section {
  margin-bottom: 40px;
}

.life-section-title {
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
  border-bottom: 1px solid var(--border);
  padding-bottom: 8px;
  margin: 0 0 16px;
}

.book-list, .hobby-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.book-item, .hobby-item {
  display: flex;
  align-items: baseline;
  gap: 8px;
  font-size: 14px;
}

.book-item::before, .hobby-item::before {
  content: '—';
  color: var(--border);
  flex-shrink: 0;
}

/* =========================================================
   Page header (sub-pages)
   ========================================================= */
.page-header {
  margin-bottom: 36px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--border);
}

.page-header h1 {
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 26px;
  font-weight: 700;
  color: var(--text);
  margin: 0 0 6px;
}

.page-header p {
  font-size: 14px;
  color: var(--text-muted);
  margin: 0;
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 13px;
  color: var(--text-muted);
  margin-bottom: 24px;
}
.back-link:hover { color: var(--accent); text-decoration: none; }

/* =========================================================
   Footer
   ========================================================= */
.footer {
  margin-top: 60px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 12px;
  color: var(--text-muted);
  text-align: center;
}

/* =========================================================
   Back to top
   ========================================================= */
#back_top {
  position: fixed;
  right: 28px;
  bottom: 28px;
  width: 38px;
  height: 38px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 50%;
  cursor: pointer;
  display: none;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-sm);
  transition: box-shadow 0.15s;
  z-index: 50;
}
#back_top:hover { box-shadow: var(--shadow-md); }
#back_top svg { color: var(--text-muted); }

/* =========================================================
   Responsive
   ========================================================= */
@media (max-width: 640px) {
  .hero { flex-direction: column; align-items: center; text-align: center; gap: 20px; }
  .hero-social { justify-content: center; }
  .hero-location { justify-content: center; }
  .pub-card { flex-direction: column; }
  .pub-img { width: 100%; height: 160px; }
  .exp-row { flex-direction: column; gap: 2px; }
  .exp-date { min-width: unset; }
  .container { padding: 24px 16px 60px; }
  .navbar { padding: 0 16px; }
}