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

:root {
  --bg-primary: #0a0a0a;
  --bg-secondary: #111111;
  --bg-tertiary: #1a1a1a;
  --bg-hover: #1e1e1e;
  --bg-active: #252525;
  --border-color: #222222;
  --border-focus: #3a3a3a;
  --text-primary: #e8e8e8;
  --text-secondary: #8a8a8a;
  --text-muted: #555555;
  --accent: #4a90e2;
  --accent-hover: #5a9ef2;
  --accent-dim: rgba(74, 144, 226, 0.12);
  --accent-glow: rgba(74, 144, 226, 0.25);
  --danger: #c0392b;
  --danger-hover: #e74c3c;
  --success: #27ae60;
  --warning: #f39c12;
  --radius: 8px;
  --radius-lg: 12px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.3);
  --shadow: 0 4px 12px rgba(0,0,0,0.4);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.5);
  --transition: 0.2s ease;
}

html, body {
  height: 100%;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  font-size: 14px;
  line-height: 1.6;
  overflow: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

a:hover {
  color: var(--accent-hover);
}

::-webkit-scrollbar {
  width: 5px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: #2a2a2a;
  border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
  background: #3a3a3a;
}

input, textarea, select, button {
  font-family: inherit;
  font-size: inherit;
  color: inherit;
}

input[type="text"],
input[type="password"],
input[type="email"],
input[type="number"],
input[type="url"],
textarea,
select {
  width: 100%;
  padding: 10px 14px;
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  color: var(--text-primary);
  outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
}

input:focus,
textarea:focus,
select:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 2px var(--accent-dim);
}

textarea {
  resize: vertical;
  min-height: 80px;
}

select {
  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 12 12'%3E%3Cpath fill='%23888' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: 32px;
}

label {
  display: block;
  margin-bottom: 6px;
  color: var(--text-secondary);
  font-size: 13px;
  font-weight: 500;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 8px 16px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  background: var(--bg-tertiary);
  color: var(--text-primary);
  cursor: pointer;
  transition: all var(--transition);
  white-space: nowrap;
  font-size: 13px;
  font-weight: 500;
  line-height: 1.4;
}

.btn:hover {
  background: var(--bg-hover);
  border-color: var(--border-focus);
  transform: translateY(-1px);
}

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

.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.btn-primary:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
  box-shadow: 0 2px 8px var(--accent-glow);
}

.btn-danger {
  background: transparent;
  border-color: var(--danger);
  color: var(--danger);
}

.btn-danger:hover {
  background: var(--danger);
  color: #fff;
  border-color: var(--danger);
}

.btn-sm {
  padding: 5px 10px;
  font-size: 12px;
  border-radius: 6px;
}

.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
  transform: none;
}

.card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 24px;
  transition: border-color var(--transition);
}

.card:hover {
  border-color: var(--border-focus);
}

.form-group {
  margin-bottom: 18px;
}

.form-group label {
  font-weight: 500;
}

.form-hint {
  font-size: 11px;
  color: var(--text-muted);
  margin-top: 4px;
  line-height: 1.4;
}

.alert {
  padding: 12px 16px;
  border-radius: var(--radius);
  margin-bottom: 18px;
  font-size: 13px;
  line-height: 1.5;
}

.alert-error {
  background: rgba(192, 57, 43, 0.12);
  border: 1px solid rgba(192, 57, 43, 0.25);
  color: var(--danger-hover);
}

.alert-success {
  background: rgba(39, 174, 96, 0.12);
  border: 1px solid rgba(39, 174, 96, 0.25);
  color: var(--success);
}

.table-wrapper {
  overflow-x: auto;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
}

table {
  width: 100%;
  border-collapse: collapse;
}

th, td {
  padding: 12px 16px;
  text-align: left;
  border-bottom: 1px solid var(--border-color);
  font-size: 13px;
}

th {
  color: var(--text-secondary);
  font-weight: 500;
  background: var(--bg-tertiary);
  position: sticky;
  top: 0;
  z-index: 1;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

tr:last-child td {
  border-bottom: none;
}

tr:hover td {
  background: rgba(255,255,255,0.015);
}

.badge {
  display: inline-flex;
  align-items: center;
  padding: 3px 10px;
  border-radius: 12px;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.3px;
}

.badge-active {
  background: rgba(39, 174, 96, 0.12);
  color: var(--success);
}

.badge-inactive {
  background: rgba(192, 57, 43, 0.12);
  color: var(--danger);
}

.badge-admin {
  background: var(--accent-dim);
  color: var(--accent);
}

.modal-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0,0,0,0.75);
  backdrop-filter: blur(4px);
  z-index: 1000;
  align-items: center;
  justify-content: center;
}

.modal-overlay.active {
  display: flex;
}

.modal {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 28px;
  width: 90%;
  max-width: 500px;
  max-height: 80vh;
  overflow-y: auto;
  box-shadow: var(--shadow-lg);
  animation: modalIn 0.2s ease;
}

@keyframes modalIn {
  from { opacity: 0; transform: scale(0.95) translateY(8px); }
  to { opacity: 1; transform: scale(1) translateY(0); }
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 24px;
}

.modal-header h3 {
  font-size: 17px;
  font-weight: 600;
}

.modal-close {
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 22px;
  padding: 4px 8px;
  border-radius: 6px;
  transition: all var(--transition);
  line-height: 1;
}

.modal-close:hover {
  color: var(--text-primary);
  background: var(--bg-hover);
}

.page-layout {
  display: flex;
  height: 100vh;
}

.sidebar {
  width: 250px;
  background: var(--bg-secondary);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  flex-shrink: 0;
}

.sidebar-header {
  padding: 18px 20px;
  border-bottom: 1px solid var(--border-color);
}

.sidebar-header h1 {
  font-size: 18px;
  font-weight: 700;
  letter-spacing: 2px;
  background: linear-gradient(135deg, var(--text-primary), var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.sidebar-nav {
  flex: 1;
  overflow-y: auto;
  padding: 10px 8px;
}

.sidebar-nav a {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 14px;
  border-radius: var(--radius);
  color: var(--text-secondary);
  font-size: 13px;
  font-weight: 500;
  transition: all var(--transition);
  margin-bottom: 2px;
}

.sidebar-nav a:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.sidebar-nav a.active {
  background: var(--accent-dim);
  color: var(--accent);
  font-weight: 600;
}

.sidebar-footer {
  padding: 14px 20px;
  border-top: 1px solid var(--border-color);
  font-size: 12px;
  color: var(--text-muted);
}

.main-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  min-width: 0;
}

.page-header {
  padding: 16px 28px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-shrink: 0;
  background: var(--bg-secondary);
}

.page-header h2 {
  font-size: 17px;
  font-weight: 600;
}

.page-header-actions {
  display: flex;
  gap: 8px;
  align-items: center;
}

.page-body {
  flex: 1;
  overflow-y: auto;
  padding: 28px;
}

.page-body-narrow {
  max-width: 640px;
}

.pagination {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: 20px;
  justify-content: center;
}

.pagination button {
  padding: 6px 14px;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  color: var(--text-primary);
  cursor: pointer;
  font-size: 12px;
  transition: all var(--transition);
}

.pagination button:hover:not(:disabled) {
  background: var(--bg-hover);
  border-color: var(--border-focus);
}

.pagination button:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

.pagination span {
  font-size: 12px;
  color: var(--text-secondary);
  padding: 0 8px;
}

.empty-state {
  text-align: center;
  padding: 80px 24px;
  color: var(--text-muted);
}

.empty-state p {
  margin-top: 10px;
  font-size: 14px;
}

.hamburger {
  display: none;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 22px;
  cursor: pointer;
  padding: 6px 10px;
  border-radius: 6px;
  transition: background var(--transition);
}

.hamburger:hover {
  background: var(--bg-hover);
}

.loading-spinner {
  display: inline-block;
  width: 20px;
  height: 20px;
  border: 2px solid var(--border-color);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
}

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

.auth-page {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 24px;
  background: var(--bg-primary);
}

.auth-card {
  width: 100%;
  max-width: 400px;
}

.auth-card h1 {
  text-align: center;
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 8px;
  letter-spacing: 3px;
  background: linear-gradient(135deg, var(--text-primary), var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.auth-card .subtitle {
  text-align: center;
  color: var(--text-secondary);
  font-size: 13px;
  margin-bottom: 36px;
}

.auth-card .form-group {
  margin-bottom: 20px;
}

.auth-card .btn-primary {
  width: 100%;
  padding: 12px;
  font-size: 14px;
  font-weight: 600;
  margin-top: 8px;
}

.auth-links {
  text-align: center;
  margin-top: 24px;
  font-size: 13px;
  color: var(--text-secondary);
}

.auth-links a {
  color: var(--text-secondary);
  transition: color var(--transition);
}

.auth-links a:hover {
  color: var(--accent);
}

.sidebar-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0,0,0,0.6);
  backdrop-filter: blur(2px);
  z-index: 99;
}

.stat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 14px;
  margin-bottom: 28px;
}

.stat-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 22px;
  transition: all var(--transition);
}

.stat-card:hover {
  border-color: var(--border-focus);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.stat-card .stat-value {
  font-size: 30px;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 4px;
  line-height: 1.2;
}

.stat-card .stat-label {
  font-size: 12px;
  color: var(--text-secondary);
  font-weight: 500;
}

.tabs {
  display: flex;
  gap: 0;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 24px;
}

.tab {
  padding: 11px 18px;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-secondary);
  cursor: pointer;
  border-bottom: 2px solid transparent;
  transition: all var(--transition);
  background: none;
  border-top: none;
  border-left: none;
  border-right: none;
}

.tab:hover {
  color: var(--text-primary);
}

.tab.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

.search-bar {
  display: flex;
  gap: 8px;
  margin-bottom: 20px;
}

.search-bar input {
  flex: 1;
}

.detail-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  font-size: 13px;
}

.detail-grid .detail-item {
  padding: 6px 0;
}

.detail-label {
  color: var(--text-secondary);
}

.detail-value {
  word-break: break-all;
}

.chat-item-clickable {
  padding: 10px 14px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  margin-bottom: 6px;
  cursor: pointer;
  font-size: 13px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: all var(--transition);
}

.chat-item-clickable:hover {
  background: var(--bg-hover);
  border-color: var(--border-focus);
}

.section-divider {
  margin-top: 28px;
  margin-bottom: 14px;
  font-size: 14px;
  color: var(--text-secondary);
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 10px;
  font-weight: 500;
}

.char-row {
  display: flex;
  align-items: center;
  gap: 10px;
}

.char-avatar-sm {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--bg-tertiary);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  overflow: hidden;
  font-size: 12px;
  color: var(--text-muted);
}

.char-avatar-sm img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.action-group {
  display: flex;
  gap: 4px;
}

.model-chip {
  display: inline-block;
  margin: 0 6px 6px 0;
}

.empty-table-msg {
  text-align: center;
  color: var(--text-muted);
  padding: 40px;
}

.loading-center {
  text-align: center;
  padding: 20px;
}

@media (max-width: 768px) {
  .sidebar {
    position: fixed;
    left: -280px;
    top: 0;
    bottom: 0;
    z-index: 100;
    width: 280px;
    transition: left 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: none;
  }

  .sidebar.open {
    left: 0;
    box-shadow: var(--shadow-lg);
  }

  .sidebar-overlay.active {
    display: block;
  }

  .hamburger {
    display: block;
  }

  .page-body {
    padding: 18px;
  }

  .page-header {
    padding: 14px 18px;
  }

  .stat-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
  }

  .stat-card {
    padding: 16px;
  }

  .stat-card .stat-value {
    font-size: 24px;
  }

  .modal {
    width: 94%;
    padding: 22px;
    margin: 16px;
  }

  th, td {
    padding: 10px 12px;
    font-size: 12px;
  }

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

  .card {
    padding: 18px;
  }
}

@media (max-width: 480px) {
  .stat-grid {
    grid-template-columns: 1fr 1fr;
    gap: 8px;
  }

  .stat-card {
    padding: 14px;
  }

  .stat-card .stat-value {
    font-size: 22px;
  }

  .page-header {
    flex-wrap: wrap;
    gap: 10px;
  }

  .page-header-actions {
    width: 100%;
    flex-wrap: wrap;
  }

  .tabs {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
  }

  .tab {
    padding: 10px 14px;
    white-space: nowrap;
    flex-shrink: 0;
  }

  .chat-item-clickable {
    padding: 8px 10px;
    font-size: 12px;
  }
}