:root {
  --bg-color: #f4f4f9;
  --card-bg: #ffffff;
  --text-primary: #2c3e50;
  --text-secondary: #546e7a;
  --accent-color: #2980b9;
  --accent-light: #eaf2f8;
  --accent-gradient: linear-gradient(135deg, #2980b9 0%, #6dd5fa 100%);
  --border-color: #e0e0e0;
  --timeline-line: #bdc3c7;
  --shadow-sm: 0 2px 4px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.12);
  --font-serif: "Merriweather", "Georgia", serif;
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;
  --transition-slow: 0.4s ease;
  --nav-width: 240px;
  --header-height: 60px;
}

/* Dark Theme */
[data-theme="dark"] {
  --bg-color: #1a1a2e;
  --card-bg: #16213e;
  --text-primary: #eaeaea;
  --text-secondary: #a0a0a0;
  --accent-color: #4fc3f7;
  --accent-light: #1e3a5f;
  --accent-gradient: linear-gradient(135deg, #4fc3f7 0%, #0f4c75 100%);
  --border-color: #2d3748;
  --timeline-line: #4a5568;
  --shadow-sm: 0 2px 4px rgba(0,0,0,0.2);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.3);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.4);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  background-color: var(--bg-color);
  color: var(--text-primary);
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* Smooth Scrollbar */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg-color);
}

::-webkit-scrollbar-thumb {
  background: var(--text-secondary);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--accent-color);
}

/* Header */
.top {
  background: var(--card-bg);
  border-bottom: 1px solid var(--border-color);
  padding: 0 1.5rem;
  height: var(--header-height);
  display: flex;
  justify-content: space-between;
  align-items: center;
  box-shadow: var(--shadow-sm);
  z-index: 100;
  transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand .logo {
  font-size: 1.8rem;
  animation: float 3s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-3px); }
}

.brand .title {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.brand .subtitle {
  font-size: 0.75rem;
  color: var(--text-secondary);
  margin-top: 2px;
  letter-spacing: 0.5px;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* Theme Toggle */
.theme-toggle {
  background: var(--accent-light);
  border: 1px solid var(--border-color);
  border-radius: 20px;
  padding: 6px 12px;
  cursor: pointer;
  font-size: 1rem;
  display: flex;
  align-items: center;
  gap: 6px;
  transition: all var(--transition-fast);
}

.theme-toggle:hover {
  background: var(--accent-color);
  color: white;
  transform: scale(1.05);
}

/* Search Box */
.search-box {
  position: relative;
  width: 280px;
}

.search-box input {
  width: 100%;
  padding: 8px 36px 8px 14px;
  border: 1px solid var(--border-color);
  border-radius: 20px;
  background: var(--bg-color);
  color: var(--text-primary);
  font-size: 0.9rem;
  transition: all var(--transition-fast);
}

.search-box input:focus {
  outline: none;
  border-color: var(--accent-color);
  box-shadow: 0 0 0 3px rgba(41, 128, 185, 0.15);
}

.search-box::after {
  content: "🔍";
  position: absolute;
  right: 12px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 0.9rem;
  opacity: 0.5;
}

.pill {
  font-size: 0.75rem;
  padding: 5px 14px;
  border-radius: 20px;
  background: var(--accent-light);
  color: var(--accent-color);
  font-weight: 500;
  transition: all var(--transition-fast);
}

.pill.ok {
  background: #d4edda;
  color: #155724;
}

.pill.error {
  background: #f8d7da;
  color: #721c24;
}

.pill:hover {
  transform: translateY(-1px);
}

/* Layout */
.layout {
  display: flex;
  flex: 1;
  overflow: hidden;
}

/* Sidebar Nav */
.nav {
  width: var(--nav-width);
  background: var(--card-bg);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  padding: 1rem 0;
  transition: all var(--transition-normal);
  overflow-y: auto;
}

.nav-section {
  padding: 0.5rem 1rem;
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-top: 0.5rem;
}

.navBtn {
  background: none;
  border: none;
  text-align: left;
  padding: 0.75rem 1.5rem;
  cursor: pointer;
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.9rem;
  transition: all var(--transition-fast);
  border-left: 3px solid transparent;
  display: flex;
  align-items: center;
  gap: 10px;
  position: relative;
  overflow: hidden;
}

.navBtn::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 0;
  height: 100%;
  background: var(--accent-light);
  transition: width var(--transition-fast);
  z-index: -1;
}

.navBtn:hover {
  color: var(--accent-color);
}

.navBtn:hover::before {
  width: 100%;
}

.navBtn.active {
  background: var(--accent-light);
  color: var(--accent-color);
  border-left-color: var(--accent-color);
  font-weight: 600;
}

.navBtn .nav-icon {
  font-size: 1.1rem;
  width: 24px;
  text-align: center;
}

.nav-divider {
  height: 1px;
  background: var(--border-color);
  margin: 12px 20px;
}

/* Main Content Area */
.main {
  flex: 1;
  overflow-y: auto;
  padding: 2rem;
  position: relative;
  animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Views */
h2 {
  font-family: var(--font-serif);
  margin-top: 0;
  border-bottom: 2px solid var(--accent-light);
  padding-bottom: 0.75rem;
  margin-bottom: 1.5rem;
  display: flex;
  align-items: center;
  gap: 12px;
}

h2 .icon {
  font-size: 1.5rem;
}

h3 {
  font-family: var(--font-serif);
  color: var(--accent-color);
  margin: 0 0 0.5rem 0;
}

/* Card Grid */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.5rem;
}

.card {
  background: var(--card-bg);
  border-radius: 12px;
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-color);
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: var(--accent-gradient);
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.card:hover::before {
  opacity: 1;
}

.card.clickable {
  cursor: pointer;
}

.card.featured {
  background: var(--accent-light);
  border-color: var(--accent-color);
}

.card h3 {
  margin: 0 0 0.5rem 0;
  font-family: var(--font-serif);
  color: var(--accent-color);
}

.card .meta {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 0.8rem;
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.card p {
  font-size: 0.95rem;
  line-height: 1.6;
  margin: 0;
  color: var(--text-secondary);
}

/* Stats Cards */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
  margin-bottom: 2rem;
}

.stat-card {
  background: var(--card-bg);
  border-radius: 12px;
  padding: 1.5rem;
  text-align: center;
  border: 1px solid var(--border-color);
  transition: all var(--transition-normal);
  cursor: pointer;
}

.stat-card:hover {
  transform: scale(1.02);
  box-shadow: var(--shadow-md);
}

.stat-card .stat-icon {
  font-size: 2rem;
  margin-bottom: 0.5rem;
}

.stat-card .stat-value {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--accent-color);
  font-family: var(--font-serif);
}

.stat-card .stat-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-top: 0.25rem;
}

/* Timeline View */
.timeline-container {
  position: relative;
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem 0;
}

.timeline-line {
  position: absolute;
  left: 50%;
  top: 0;
  bottom: 0;
  width: 3px;
  background: linear-gradient(to bottom, var(--accent-color), var(--timeline-line));
  transform: translateX(-50%);
  border-radius: 2px;
}

.timeline-item {
  position: relative;
  margin-bottom: 3rem;
  width: 50%;
  padding-right: 2.5rem;
  box-sizing: border-box;
  text-align: right;
  animation: slideInLeft 0.5s ease forwards;
  opacity: 0;
}

.timeline-item:nth-child(even) {
  left: 50%;
  padding-right: 0;
  padding-left: 2.5rem;
  text-align: left;
  animation: slideInRight 0.5s ease forwards;
}

@keyframes slideInLeft {
  from { opacity: 0; transform: translateX(-20px); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes slideInRight {
  from { opacity: 0; transform: translateX(20px); }
  to { opacity: 1; transform: translateX(0); }
}

.timeline-dot {
  position: absolute;
  top: 15px;
  right: -8px;
  width: 16px;
  height: 16px;
  background: var(--accent-color);
  border-radius: 50%;
  border: 3px solid var(--card-bg);
  z-index: 2;
  box-shadow: 0 0 0 3px var(--accent-light);
  transition: all var(--transition-fast);
}

.timeline-item:hover .timeline-dot {
  transform: scale(1.3);
  box-shadow: 0 0 0 6px var(--accent-light);
}

.timeline-item:nth-child(even) .timeline-dot {
  right: auto;
  left: -8px;
}

.timeline-year {
  font-weight: 900;
  font-size: 1.5rem;
  color: var(--accent-color);
  font-family: var(--font-serif);
  margin-bottom: 0.5rem;
}

.timeline-content {
  background: var(--card-bg);
  padding: 1.25rem;
  border-radius: 12px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-color);
  transition: all var(--transition-normal);
}

.timeline-item:hover .timeline-content {
  box-shadow: var(--shadow-md);
}

.timeline-content h3 {
  margin: 0 0 0.5rem 0;
  font-size: 1rem;
}

.timeline-content p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin: 0;
  line-height: 1.5;
}

/* Graph Container */
#graph-viz, #social-viz {
  width: 100%;
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  box-shadow: var(--shadow-sm);
}

#graph-viz {
  height: 700px;
}

#social-viz {
  height: 600px;
}

/* Scholar Profile */
.scholar-profile {
  display: grid;
  grid-template-columns: 320px 1fr;
  gap: 2rem;
}

.scholar-avatar {
  width: 100px;
  height: 100px;
  background: var(--accent-gradient);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 2.5rem;
  font-family: var(--font-serif);
  margin: 0 auto 1.5rem;
  box-shadow: var(--shadow-md);
}

/* CSV Editor */
textarea.csv-editor {
  width: 100%;
  height: 450px;
  font-family: "Fira Code", "JetBrains Mono", monospace;
  font-size: 0.9rem;
  padding: 1.25rem;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  background: var(--card-bg);
  color: var(--text-primary);
  resize: vertical;
  transition: all var(--transition-fast);
}

textarea.csv-editor:focus {
  outline: none;
  border-color: var(--accent-color);
  box-shadow: 0 0 0 3px rgba(41, 128, 185, 0.15);
}

.action-bar {
  margin-bottom: 1rem;
  display: flex;
  gap: 1rem;
  align-items: center;
  flex-wrap: wrap;
}

button.primary {
  background: var(--accent-gradient);
  color: #fff;
  border: none;
  padding: 0.6rem 1.25rem;
  border-radius: 8px;
  cursor: pointer;
  font-weight: 600;
  font-size: 0.9rem;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  gap: 6px;
}

button.primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

button.secondary {
  background: var(--bg-color);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  padding: 0.6rem 1.25rem;
  border-radius: 8px;
  cursor: pointer;
  font-weight: 500;
  transition: all var(--transition-fast);
}

button.secondary:hover {
  background: var(--accent-light);
  border-color: var(--accent-color);
}

/* Filter Controls */
.filter-bar {
  display: flex;
  gap: 1rem;
  align-items: center;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
  padding: 1rem;
  background: var(--card-bg);
  border-radius: 12px;
  border: 1px solid var(--border-color);
}

.filter-bar label {
  font-weight: 600;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 6px;
}

.filter-bar select {
  padding: 8px 12px;
  border-radius: 8px;
  border: 1px solid var(--border-color);
  background: var(--bg-color);
  color: var(--text-primary);
  font-family: var(--font-sans);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.filter-bar select:focus {
  outline: none;
  border-color: var(--accent-color);
}

.filter-bar .hint {
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-left: auto;
}

/* Loading Spinner */
.loading {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 3rem;
}

.spinner {
  width: 40px;
  height: 40px;
  border: 3px solid var(--border-color);
  border-top-color: var(--accent-color);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* Empty State */
.empty-state {
  text-align: center;
  padding: 4rem 2rem;
  color: var(--text-secondary);
}

.empty-state .icon {
  font-size: 4rem;
  margin-bottom: 1rem;
  opacity: 0.5;
}

/* Back Button */
.back-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 0.5rem 1rem;
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  border-radius: 8px;
  transition: all var(--transition-fast);
  cursor: pointer;
  background: none;
  border: none;
  font-size: 0.9rem;
}

.back-btn:hover {
  color: var(--accent-color);
  background: var(--accent-light);
}

/* Responsive Design */
@media (max-width: 1024px) {
  .scholar-profile {
    grid-template-columns: 1fr;
  }

  .card-grid {
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  }
}

@media (max-width: 768px) {
  :root {
    --nav-width: 60px;
  }

  .nav {
    width: var(--nav-width);
  }

  .navBtn {
    padding: 0.75rem;
    justify-content: center;
  }

  .navBtn .nav-text {
    display: none;
  }

  .navBtn .nav-icon {
    font-size: 1.3rem;
  }

  .nav-section, .nav-divider {
    display: none;
  }

  .brand .subtitle {
    display: none;
  }

  .search-box {
    width: 180px;
  }

  .main {
    padding: 1rem;
  }

  .timeline-line {
    left: 20px;
  }

  .timeline-item,
  .timeline-item:nth-child(even) {
    width: 100%;
    left: 0;
    padding-left: 50px;
    padding-right: 0;
    text-align: left;
  }

  .timeline-dot,
  .timeline-item:nth-child(even) .timeline-dot {
    left: 12px;
    right: auto;
  }
}

@media (max-width: 480px) {
  .header-actions {
    gap: 8px;
  }

  .search-box {
    width: 120px;
  }

  .search-box input {
    font-size: 0.8rem;
    padding: 6px 10px;
  }

  .stats-grid {
    grid-template-columns: 1fr 1fr;
  }

  .card-grid {
    grid-template-columns: 1fr;
  }
}

/* Print Styles */
@media print {
  .nav, .top, .action-bar {
    display: none;
  }

  .main {
    padding: 0;
  }

  .card {
    break-inside: avoid;
    box-shadow: none;
    border: 1px solid #ddd;
  }
}

/* Tooltip */
.tooltip {
  position: relative;
}

.tooltip::after {
  content: attr(data-tooltip);
  position: absolute;
  bottom: 100%;
  left: 50%;
  transform: translateX(-50%);
  padding: 6px 12px;
  background: var(--text-primary);
  color: var(--bg-color);
  font-size: 0.75rem;
  border-radius: 4px;
  white-space: nowrap;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-fast);
}

.tooltip:hover::after {
  opacity: 1;
  visibility: visible;
}

/* Animation utilities */
.fade-in {
  animation: fadeIn 0.3s ease;
}

.slide-up {
  animation: slideUp 0.4s ease;
}

@keyframes slideUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Influence Network Styles */
.influence-legend {
  display: flex;
  gap: 1.5rem;
  padding: 1rem;
  background: var(--card-bg);
  border-radius: 8px;
  margin-bottom: 1rem;
  flex-wrap: wrap;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.legend-dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
}

/* Badge Styles */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 3px 10px;
  border-radius: 12px;
  font-size: 0.75rem;
  font-weight: 600;
}

.badge.scholar {
  background: #e3f2fd;
  color: #1565c0;
}

.badge.theory {
  background: #f3e5f5;
  color: #7b1fa2;
}

.badge.event {
  background: #fff3e0;
  color: #e65100;
}

[data-theme="dark"] .badge.scholar {
  background: #1e3a5f;
  color: #4fc3f7;
}

[data-theme="dark"] .badge.theory {
  background: #3d1f47;
  color: #ce93d8;
}

[data-theme="dark"] .badge.event {
  background: #4a2c00;
  color: #ffb74d;
}

/* Footer */
.footer {
  background: var(--card-bg);
  border-top: 1px solid var(--border-color);
  padding: 1rem 2rem;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-top: auto;
}

.footer-content {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 0.5rem;
}

.footer-content strong {
  color: var(--accent-color);
  font-weight: 600;
}

.footer-divider {
  color: var(--border-color);
}

[data-theme="dark"] .footer {
  background: var(--card-bg);
  border-top-color: var(--border-color);
}