/* ===== 讲课网小程序管理后台 - 暗色科技主题 ===== */
:root {
  --bg-dark: #0f172a;
  --bg-card: #1e293b;
  --bg-hover: #334155;
  --border: #334155;
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent: #3b82f6;
  --accent-light: #60a5fa;
  --accent-gradient: linear-gradient(135deg, #3b82f6 0%, #8b5cf6 100%);
  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.3);
}

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

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

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

/* === 布局 === */
.admin-layout {
  display: flex;
  min-height: 100vh;
}

.sidebar {
  width: 220px;
  background: #0c1322;
  border-right: 1px solid var(--border);
  padding: 20px 0;
  position: fixed;
  top: 0; left: 0; bottom: 0;
  overflow-y: auto;
  z-index: 100;
}

.sidebar-brand {
  padding: 20px 24px;
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
}

.sidebar-brand-icon {
  font-size: 28px;
}

.sidebar-brand-text {
  font-size: 16px;
  font-weight: 700;
  color: var(--text-primary);
}

.sidebar-brand-sub {
  font-size: 11px;
  color: var(--text-muted);
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 24px;
  color: var(--text-secondary);
  font-size: 14px;
  transition: all 0.2s;
  border-left: 3px solid transparent;
}

.nav-item:hover {
  background: var(--bg-card);
  color: var(--text-primary);
  text-decoration: none;
}

.nav-item.active {
  background: rgba(59, 130, 246, 0.15);
  color: var(--accent-light);
  border-left-color: var(--accent);
}

.nav-icon { font-size: 18px; }

.main {
  flex: 1;
  margin-left: 220px;
  padding: 32px;
}

/* === 顶栏 === */
.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
}

.page-title {
  font-size: 22px;
  font-weight: 700;
}

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

.user-info {
  font-size: 13px;
  color: var(--text-secondary);
}

/* === 卡片 === */
.card {
  background: var(--bg-card);
  border-radius: var(--radius);
  padding: 24px;
  margin-bottom: 20px;
  box-shadow: var(--shadow);
}

.card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border);
}

.card-title {
  font-size: 16px;
  font-weight: 600;
}

/* === 表单 === */
.form-group {
  margin-bottom: 18px;
}

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

.form-input, .form-textarea, .form-select {
  width: 100%;
  padding: 10px 14px;
  background: var(--bg-dark);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 14px;
  transition: border 0.2s;
}

.form-input:focus, .form-textarea:focus, .form-select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.form-textarea {
  min-height: 100px;
  resize: vertical;
  font-family: monospace;
}

.form-hint {
  font-size: 12px;
  color: var(--text-muted);
  margin-top: 4px;
}

/* === 按钮 === */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 20px;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
  text-decoration: none;
}

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

.btn-primary:hover { opacity: 0.9; text-decoration: none; }

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

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

.btn-sm {
  padding: 6px 14px;
  font-size: 12px;
}

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

/* === 开关 === */
.switch {
  position: relative;
  display: inline-block;
  width: 48px;
  height: 26px;
}

.switch input { display: none; }

.switch-slider {
  position: absolute;
  inset: 0;
  background: var(--border);
  border-radius: 999px;
  transition: 0.3s;
  cursor: pointer;
}

.switch-slider::before {
  content: '';
  position: absolute;
  height: 20px;
  width: 20px;
  left: 3px;
  bottom: 3px;
  background: #fff;
  border-radius: 50%;
  transition: 0.3s;
}

.switch input:checked + .switch-slider {
  background: var(--success);
}

.switch input:checked + .switch-slider::before {
  transform: translateX(22px);
}

/* === 统计卡片 === */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
  margin-bottom: 24px;
}

.stat-card {
  background: var(--bg-card);
  border-radius: var(--radius);
  padding: 20px;
  box-shadow: var(--shadow);
  border-left: 4px solid var(--accent);
}

.stat-card.warning { border-left-color: var(--warning); }
.stat-card.success { border-left-color: var(--success); }
.stat-card.danger { border-left-color: var(--danger); }

.stat-label {
  font-size: 13px;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

.stat-value {
  font-size: 28px;
  font-weight: 700;
  color: var(--text-primary);
}

.stat-extra {
  font-size: 12px;
  color: var(--text-muted);
  margin-top: 4px;
}

/* === 表格 === */
.table {
  width: 100%;
  border-collapse: collapse;
}

.table th, .table td {
  padding: 12px 16px;
  text-align: left;
  border-bottom: 1px solid var(--border);
  font-size: 14px;
}

.table th {
  color: var(--text-secondary);
  font-weight: 600;
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.table tbody tr:hover {
  background: rgba(59, 130, 246, 0.05);
}

/* === 标签 === */
.badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
}

.badge-success { background: rgba(16, 185, 129, 0.2); color: var(--success); }
.badge-danger { background: rgba(239, 68, 68, 0.2); color: var(--danger); }
.badge-warning { background: rgba(245, 158, 11, 0.2); color: var(--warning); }
.badge-info { background: rgba(59, 130, 246, 0.2); color: var(--accent-light); }

/* === 登录页 === */
.login-container {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  background: var(--bg-dark);
}

.login-card {
  background: var(--bg-card);
  border-radius: var(--radius);
  padding: 40px;
  width: 100%;
  max-width: 400px;
  box-shadow: var(--shadow);
}

.login-title {
  text-align: center;
  font-size: 24px;
  font-weight: 700;
  margin-bottom: 8px;
}

.login-subtitle {
  text-align: center;
  font-size: 14px;
  color: var(--text-secondary);
  margin-bottom: 32px;
}

.login-error {
  background: rgba(239, 68, 68, 0.1);
  border: 1px solid var(--danger);
  color: var(--danger);
  padding: 10px 16px;
  border-radius: var(--radius-sm);
  font-size: 13px;
  margin-bottom: 16px;
}

.login-btn {
  width: 100%;
  padding: 12px;
  font-size: 15px;
}

/* === 弹窗 === */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.7);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 200;
}

.modal-card {
  background: var(--bg-card);
  border-radius: var(--radius);
  padding: 28px;
  width: 90%;
  max-width: 500px;
  box-shadow: var(--shadow);
}

.modal-title {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 20px;
}

.modal-actions {
  display: flex;
  gap: 12px;
  justify-content: flex-end;
  margin-top: 20px;
}

/* === 提示 === */
.alert {
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  font-size: 13px;
  margin-bottom: 16px;
}

.alert-info {
  background: rgba(59, 130, 246, 0.1);
  border: 1px solid rgba(59, 130, 246, 0.3);
  color: var(--accent-light);
}

.alert-success {
  background: rgba(16, 185, 129, 0.1);
  border: 1px solid rgba(16, 185, 129, 0.3);
  color: var(--success);
}

.alert-warning {
  background: rgba(245, 158, 11, 0.1);
  border: 1px solid rgba(245, 158, 11, 0.3);
  color: var(--warning);
}

/* === 广告位行 === */
.ad-position-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 0;
  border-bottom: 1px solid var(--border);
}

.ad-position-row:last-child { border-bottom: none; }

.ad-position-info { flex: 1; }

.ad-position-name {
  font-size: 15px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.ad-position-desc {
  font-size: 13px;
  color: var(--text-secondary);
}

.ad-position-controls {
  display: flex;
  align-items: center;
  gap: 16px;
}

.ad-unit-input {
  width: 280px;
  padding: 8px 12px;
  background: var(--bg-dark);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 13px;
  font-family: monospace;
}

/* === 响应式 === */
@media (max-width: 768px) {
  .sidebar { width: 60px; }
  .sidebar-brand-text, .sidebar-brand-sub, .nav-item span { display: none; }
  .main { margin-left: 60px; padding: 16px; }
  .stats-grid { grid-template-columns: 1fr; }
}