:root {
  --primary-color: #4f46e5;
  --primary-hover: #4338ca;
  --secondary-color: #6366f1;
  --background: #f8fafc;
  --surface: #ffffff;
  --text-primary: #1e293b;
  --text-secondary: #64748b;
  --text-muted: #94a3b8;
  --border-color: #e2e8f0;
  --success-color: #22c55e;
  --warning-color: #f59e0b;
  --error-color: #ef4444;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --transition: all 0.2s ease;
}

@media (prefers-color-scheme: dark) {
  :root {
    --background: #0f172a;
    --surface: #1e293b;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --border-color: #334155;
  }
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background: var(--background);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
}

.app {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.header {
  background: var(--surface);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-sm);
}

.header-content {
  max-width: 1400px;
  margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
}

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary-color);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.logo-icon {
  font-size: 1.75rem;
}

.nav {
  display: flex;
  gap: 0.5rem;
}

.nav-btn {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.625rem 1.25rem;
  background: transparent;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  font-size: 0.9375rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
}

.nav-btn:hover {
  background: var(--background);
  color: var(--text-primary);
}

.nav-btn.active {
  background: var(--primary-color);
  border-color: var(--primary-color);
  color: white;
}

.nav-icon {
  font-size: 1.125rem;
}

.header-actions {
  display: flex;
  gap: 0.75rem;
}

.refresh-btn {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.625rem 1rem;
  background: var(--secondary-color);
  border: none;
  border-radius: var(--radius-md);
  color: white;
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
}

.refresh-btn:hover {
  background: var(--primary-hover);
  transform: translateY(-1px);
}

.refresh-btn:active {
  transform: translateY(0);
}

.refresh-btn.loading .refresh-icon {
  animation: spin 1s linear infinite;
}

@keyframes spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

.main {
  flex: 1;
  max-width: 1400px;
  margin: 0 auto;
  padding: 1.5rem;
  width: 100%;
}

.stats-bar {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.stat-item {
  background: var(--surface);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  text-align: center;
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
}

.stat-value {
  display: block;
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--primary-color);
  margin-bottom: 0.25rem;
}

.stat-label {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.filters {
  display: flex;
  gap: 1rem;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
}

.filter-group {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.filter-group label {
  font-size: 0.875rem;
  color: var(--text-secondary);
  white-space: nowrap;
}

.filter-select {
  padding: 0.5rem 2rem 0.5rem 0.75rem;
  background: var(--surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 0.875rem;
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.75rem center;
  transition: var(--transition);
}

.filter-select:hover {
  border-color: var(--primary-color);
}

.filter-select:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.content {
  min-height: 400px;
}

.loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 4rem 2rem;
  color: var(--text-secondary);
}

.loading-spinner {
  width: 48px;
  height: 48px;
  border: 3px solid var(--border-color);
  border-top-color: var(--primary-color);
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin-bottom: 1rem;
}

.error-message {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  padding: 2rem;
  background: rgba(239, 68, 68, 0.1);
  border: 1px solid var(--error-color);
  border-radius: var(--radius-lg);
  color: var(--error-color);
  margin-bottom: 1.5rem;
}

.retry-btn {
  padding: 0.5rem 1rem;
  background: var(--error-color);
  border: none;
  border-radius: var(--radius-md);
  color: white;
  font-size: 0.875rem;
  cursor: pointer;
  transition: var(--transition);
}

.retry-btn:hover {
  opacity: 0.9;
}

.ranking-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1rem;
}

.ranking-card {
  background: var(--surface);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  cursor: pointer;
  display: flex;
  gap: 1rem;
}

.ranking-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
  border-color: var(--primary-color);
}

.card-rank {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  border-radius: var(--radius-md);
  color: white;
  font-size: 1.25rem;
  font-weight: 700;
  flex-shrink: 0;
}

.card-rank.top-3 {
  background: linear-gradient(135deg, #fbbf24, #f59e0b);
}

.card-content {
  flex: 1;
  min-width: 0;
}

.card-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.card-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  font-size: 0.8125rem;
  color: var(--text-secondary);
}

.card-meta-item {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.card-source {
  display: inline-flex;
  padding: 0.25rem 0.5rem;
  background: var(--background);
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 0.5rem;
}

.card-score {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  color: var(--warning-color);
  font-weight: 500;
}

.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 4rem 2rem;
  color: var(--text-secondary);
}

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

.pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  margin-top: 2rem;
  padding: 1rem 0;
}

.page-btn {
  padding: 0.625rem 1.25rem;
  background: var(--surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 0.875rem;
  cursor: pointer;
  transition: var(--transition);
}

.page-btn:hover:not(:disabled) {
  background: var(--primary-color);
  border-color: var(--primary-color);
  color: white;
}

.page-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.page-info {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.footer {
  background: var(--surface);
  border-top: 1px solid var(--border-color);
  padding: 1.5rem;
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.875rem;
}

@media (max-width: 768px) {
  .header-content {
    flex-direction: column;
    align-items: stretch;
  }

  .nav {
    justify-content: center;
    flex-wrap: wrap;
  }

  .nav-btn {
    flex: 1;
    min-width: 100px;
    justify-content: center;
  }

  .header-actions {
    justify-content: center;
  }

  .filters {
    flex-direction: column;
  }

  .filter-group {
    width: 100%;
  }

  .filter-select {
    flex: 1;
  }

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

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

@media (max-width: 480px) {
  .logo {
    font-size: 1.25rem;
  }

  .nav-btn {
    padding: 0.5rem 0.75rem;
    font-size: 0.8125rem;
  }

  .nav-icon {
    display: none;
  }

  .refresh-text {
    display: none;
  }

  .ranking-card {
    padding: 1rem;
  }

  .card-rank {
    width: 40px;
    height: 40px;
    font-size: 1rem;
  }
}