/* =========================================================
   仲龙教学管理系统 v2.0 - 主样式表
   品牌色: 深蓝 #1a4b8c / 金色 #c9a84c
   ========================================================= */

/* ---- CSS Variables: Light Theme (默认) ---- */
:root {
  --sidebar-width: 240px;
  --sidebar-bg: #f8f9fc;
  --sidebar-border: #e8ecf1;
  --sidebar-text: #3a4a5e;
  --sidebar-text-muted: #8a96a8;
  --sidebar-hover-bg: #eef0f5;
  --sidebar-active-bg: #1a4b8c;
  --sidebar-active-text: #ffffff;
  --sidebar-logo-text: #1a4b8c;

  --topbar-bg: #ffffff;
  --topbar-border: #e8ecf1;
  --topbar-text: #3a4a5e;

  --content-bg: #f0f2f7;
  --card-bg: #ffffff;
  --card-border: #e8ecf1;
  --card-shadow: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);

  --text-primary: #1a2a3a;
  --text-secondary: #5a6a7a;
  --text-muted: #8a96a8;

  --brand-primary: #1a4b8c;
  --brand-primary-hover: #153d73;
  --brand-accent: #c9a84c;
  --brand-accent-hover: #b8972f;

  --input-bg: #ffffff;
  --input-border: #d0d5dd;
  --input-focus-border: #1a4b8c;
  --input-focus-shadow: rgba(26, 75, 140, 0.15);

  --table-header-bg: #f4f6fa;
  --table-border: #e8ecf1;
  --table-hover-bg: #f0f4ff;

  --badge-bg: #eef0f5;
  --badge-text: #3a4a5e;

  --alert-info-bg: #e8f0fe;
  --alert-info-border: #b3d4ff;
  --alert-info-text: #1a4b8c;
  --alert-success-bg: #e6f7e6;
  --alert-success-border: #b3e0b3;
  --alert-success-text: #1a7a1a;
  --alert-danger-bg: #ffe8e8;
  --alert-danger-border: #ffb3b3;
  --alert-danger-text: #cc0000;
  --alert-warning-bg: #fff8e6;
  --alert-warning-border: #ffe0b3;
  --alert-warning-text: #996600;

  --scrollbar-thumb: #c0c4cc;
  --scrollbar-track: #f0f2f5;
  --kefu-bg: #07c160;
  --modal-overlay: rgba(0,0,0,0.35);
  --focus-ring: rgba(26, 75, 140, 0.25);

  --transition-speed: 0.2s;
}

/* ---- CSS Variables: Dark Theme ---- */
[data-theme="dark"] {
  --sidebar-bg: #1a1d23;
  --sidebar-border: #2a2d33;
  --sidebar-text: #c8cdd6;
  --sidebar-text-muted: #6a707a;
  --sidebar-hover-bg: #2a2d33;
  --sidebar-active-bg: #1a4b8c;
  --sidebar-active-text: #ffffff;
  --sidebar-logo-text: #c9a84c;

  --topbar-bg: #1a1d23;
  --topbar-border: #2a2d33;
  --topbar-text: #c8cdd6;

  --content-bg: #121418;
  --card-bg: #1a1d23;
  --card-border: #2a2d33;
  --card-shadow: 0 1px 3px rgba(0,0,0,0.3), 0 1px 2px rgba(0,0,0,0.2);

  --text-primary: #e4e8ee;
  --text-secondary: #a0a8b4;
  --text-muted: #6a707a;

  --brand-primary: #2a6bc9;
  --brand-primary-hover: #3a7bd9;
  --brand-accent: #c9a84c;
  --brand-accent-hover: #d9b85c;

  --input-bg: #262a30;
  --input-border: #3a3e44;
  --input-focus-border: #2a6bc9;
  --input-focus-shadow: rgba(42, 107, 201, 0.25);

  --table-header-bg: #22252b;
  --table-border: #2a2d33;
  --table-hover-bg: #1f2238;

  --badge-bg: #2a2d33;
  --badge-text: #c8cdd6;

  --alert-info-bg: #1a2a4a;
  --alert-info-border: #2a4a6a;
  --alert-info-text: #8ab4f8;
  --alert-success-bg: #1a2a1a;
  --alert-success-border: #2a4a2a;
  --alert-success-text: #81c784;
  --alert-danger-bg: #2a1a1a;
  --alert-danger-border: #4a2a2a;
  --alert-danger-text: #ef5350;
  --alert-warning-bg: #2a2a1a;
  --alert-warning-border: #4a4a2a;
  --alert-warning-text: #ffca28;

  --scrollbar-thumb: #3a3e44;
  --scrollbar-track: #1a1d23;
  --modal-overlay: rgba(0,0,0,0.55);
  --focus-ring: rgba(42, 107, 201, 0.35);

  /* Override Bootstrap dark colors */
  --bs-body-bg: #121418;
  --bs-body-color: #e4e8ee;
}

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

html {
  font-size: 15px;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  padding: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  background: var(--content-bg);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
  transition: background var(--transition-speed) ease, color var(--transition-speed) ease;
}

/* ---- Layout: Sidebar + Main ---- */
.app-layout {
  display: flex;
  min-height: 100vh;
}

/* ---- Sidebar ---- */
.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidebar-width);
  height: 100vh;
  background: var(--sidebar-bg);
  border-right: 1px solid var(--sidebar-border);
  display: flex;
  flex-direction: column;
  z-index: 1030;
  transition: background var(--transition-speed) ease, border-color var(--transition-speed) ease;
  overflow-y: auto;
  overflow-x: hidden;
}

/* Sidebar scrollbar styling */
.sidebar::-webkit-scrollbar {
  width: 4px;
}
.sidebar::-webkit-scrollbar-thumb {
  background: var(--scrollbar-thumb);
  border-radius: 2px;
}
.sidebar::-webkit-scrollbar-track {
  background: var(--scrollbar-track);
}

/* Logo area */
.sidebar-logo {
  display: flex;
  align-items: center;
  padding: 20px 20px 16px;
  gap: 10px;
  border-bottom: 1px solid var(--sidebar-border);
  transition: border-color var(--transition-speed) ease;
  flex-shrink: 0;
}

.sidebar-logo .logo-icon {
  width: 38px;
  height: 38px;
  background: linear-gradient(135deg, var(--brand-primary), #2a5a9c);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 20px;
  flex-shrink: 0;
}

.sidebar-logo .logo-text {
  font-size: 16px;
  font-weight: 700;
  color: var(--sidebar-logo-text);
  line-height: 1.3;
  transition: color var(--transition-speed) ease;
}

.sidebar-logo .logo-sub {
  font-size: 11px;
  color: var(--sidebar-text-muted);
  font-weight: 400;
  display: block;
  margin-top: 1px;
  transition: color var(--transition-speed) ease;
}

/* Navigation menu */
.sidebar-nav {
  flex: 1;
  padding: 12px 0;
  list-style: none;
  margin: 0;
}

.sidebar-nav .nav-section {
  padding: 8px 20px 4px;
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--sidebar-text-muted);
  transition: color var(--transition-speed) ease;
}

.sidebar-nav .nav-item {
  margin: 1px 8px;
}

.sidebar-nav .nav-link {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 14px;
  border-radius: 8px;
  color: var(--sidebar-text);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  transition: all var(--transition-speed) ease;
  position: relative;
}

.sidebar-nav .nav-link i {
  width: 20px;
  text-align: center;
  font-size: 16px;
  flex-shrink: 0;
}

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

.sidebar-nav .nav-link.active {
  background: var(--sidebar-active-bg);
  color: var(--sidebar-active-text);
  font-weight: 600;
  box-shadow: 0 2px 6px rgba(26, 75, 140, 0.25);
}

.sidebar-nav .nav-link.active i {
  color: inherit;
}

/* Sidebar bottom area (dark mode toggle + copyright) */
.sidebar-bottom {
  border-top: 1px solid var(--sidebar-border);
  padding: 12px 16px;
  flex-shrink: 0;
  transition: border-color var(--transition-speed) ease;
}

/* Dark mode toggle */
.dark-mode-toggle {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 10px;
  border-radius: 8px;
  cursor: pointer;
  transition: background var(--transition-speed) ease;
  user-select: none;
}

.dark-mode-toggle:hover {
  background: var(--sidebar-hover-bg);
}

.dark-mode-toggle .toggle-label {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--sidebar-text);
  transition: color var(--transition-speed) ease;
}

.dark-mode-toggle .toggle-label i {
  font-size: 14px;
  width: 16px;
  text-align: center;
}

/* Custom toggle switch */
.toggle-switch {
  position: relative;
  width: 40px;
  height: 22px;
  background: #c0c4cc;
  border-radius: 11px;
  transition: background var(--transition-speed) ease;
  flex-shrink: 0;
}

[data-theme="dark"] .toggle-switch {
  background: var(--brand-primary);
}

.toggle-switch::after {
  content: '';
  position: absolute;
  top: 2px;
  left: 2px;
  width: 18px;
  height: 18px;
  background: #fff;
  border-radius: 50%;
  transition: transform var(--transition-speed) ease;
  box-shadow: 0 1px 3px rgba(0,0,0,0.2);
}

[data-theme="dark"] .toggle-switch::after {
  transform: translateX(18px);
}

/* Copyright */
.sidebar-copyright {
  padding: 6px 10px 2px;
  font-size: 11px;
  color: var(--sidebar-text-muted);
  line-height: 1.5;
  text-align: center;
  transition: color var(--transition-speed) ease;
}

/* Storage info bar in sidebar */
.storage-info {
  padding: 10px 16px;
  border-top: 1px solid var(--sidebar-border);
  flex-shrink: 0;
}
.storage-label {
  font-size: 11px;
  color: var(--sidebar-text-muted);
  margin-bottom: 4px;
}
.storage-bar-wrapper {
  height: 6px;
  background: var(--sidebar-hover);
  border-radius: 3px;
  overflow: hidden;
  margin-bottom: 2px;
}
.storage-bar {
  height: 100%;
  background: var(--primary, #3b82f6);
  border-radius: 3px;
  transition: width 0.3s ease;
}
.storage-bar.warning { background: #f59e0b; }
.storage-bar.danger { background: #ef4444; }
.storage-text {
  font-size: 10px;
  color: var(--sidebar-text-muted);
}

/* ---- Main Content Area ---- */
.main-content {
  margin-left: var(--sidebar-width);
  flex: 1;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  transition: margin-left var(--transition-speed) ease;
}

/* Top bar */
.topbar {
  background: var(--topbar-bg);
  border-bottom: 1px solid var(--topbar-border);
  padding: 12px 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  transition: background var(--transition-speed) ease, border-color var(--transition-speed) ease;
  flex-shrink: 0;
  min-height: 60px;
}

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

.topbar-left .page-title {
  font-size: 17px;
  font-weight: 600;
  color: var(--text-primary);
  margin: 0;
  transition: color var(--transition-speed) ease;
}

/* Mobile hamburger */
.sidebar-toggle-btn {
  display: none;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 20px;
  cursor: pointer;
  padding: 4px 8px;
  border-radius: 6px;
  transition: background var(--transition-speed) ease;
}

.sidebar-toggle-btn:hover {
  background: var(--sidebar-hover-bg);
}

.topbar-right {
  display: flex;
  align-items: center;
  gap: 16px;
}

.topbar-user {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--text-secondary);
  transition: color var(--transition-speed) ease;
}

.topbar-user .user-avatar {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--brand-primary), #2a5a9c);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 600;
}

.topbar-user .user-name {
  font-weight: 500;
  color: var(--text-primary);
  transition: color var(--transition-speed) ease;
}

.topbar-user .user-role {
  font-size: 12px;
  color: var(--text-muted);
}

.btn-logout {
  padding: 6px 14px;
  font-size: 13px;
  border-radius: 6px;
  border: 1px solid var(--card-border);
  background: transparent;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 6px;
  cursor: pointer;
  text-decoration: none;
  transition: all var(--transition-speed) ease;
}

.btn-logout:hover {
  background: var(--sidebar-hover-bg);
  color: var(--brand-primary);
  border-color: var(--brand-primary);
}

/* Content area */
.content-area {
  flex: 1;
  padding: 24px 28px;
  overflow-y: auto;
}

/* ---- Card ---- */
.card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 12px;
  box-shadow: var(--card-shadow);
  transition: all var(--transition-speed) ease;
}

.card:hover {
  box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}

.card-body {
  padding: 20px;
}

.card-header {
  background: transparent;
  border-bottom: 1px solid var(--card-border);
  padding: 16px 20px;
  border-radius: 12px 12px 0 0;
  transition: border-color var(--transition-speed) ease;
}

/* ---- Stat Card ---- */
.stat-card {
  padding: 20px;
}
.stat-card .icon {
  font-size: 32px;
  opacity: 0.85;
}
.stat-card .number {
  font-size: 28px;
  font-weight: 700;
  color: var(--text-primary);
}

/* ---- Tables ---- */
.table {
  color: var(--text-primary);
  border-color: var(--table-border);
  margin-bottom: 0;
  transition: color var(--transition-speed) ease, border-color var(--transition-speed) ease;
}

.table th {
  border-top: none;
  background: var(--table-header-bg);
  color: var(--text-secondary);
  font-weight: 600;
  font-size: 13px;
  text-transform: none;
  padding: 12px 12px;
  transition: background var(--transition-speed) ease, color var(--transition-speed) ease;
}

.table td {
  padding: 12px;
  vertical-align: middle;
  border-color: var(--table-border);
  transition: border-color var(--transition-speed) ease;
}

.table-hover tbody tr:hover {
  background: var(--table-hover-bg);
}

.table-responsive {
  border-radius: 12px;
}

/* ---- Form Controls ---- */
.form-control, .form-select {
  background: var(--input-bg);
  border: 1px solid var(--input-border);
  border-radius: 8px;
  color: var(--text-primary);
  padding: 8px 12px;
  font-size: 14px;
  transition: all var(--transition-speed) ease;
}

.form-control:focus, .form-select:focus {
  border-color: var(--input-focus-border);
  box-shadow: 0 0 0 3px var(--input-focus-shadow);
  background: var(--input-bg);
  color: var(--text-primary);
}

.form-control::placeholder {
  color: var(--text-muted);
}

.form-label {
  font-size: 13px;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 4px;
  transition: color var(--transition-speed) ease;
}

/* Input groups */
.input-group .form-control,
.input-group .form-select {
  border-radius: 8px;
}

.input-group .btn {
  border-radius: 8px;
}

/* ---- Buttons ---- */
.btn {
  border-radius: 8px;
  font-size: 14px;
  padding: 8px 18px;
  font-weight: 500;
  transition: all var(--transition-speed) ease;
  border: 1px solid transparent;
}

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

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

.btn-primary:focus {
  box-shadow: 0 0 0 3px var(--focus-ring);
}

.btn-outline-primary {
  color: var(--brand-primary);
  border-color: var(--brand-primary);
  background: transparent;
}

.btn-outline-primary:hover {
  background: var(--brand-primary);
  color: #fff;
}

.btn-success {
  background: #16a34a;
  border-color: #16a34a;
}

.btn-success:hover {
  background: #15803d;
}

.btn-info {
  background: #0e7490;
  border-color: #0e7490;
}

.btn-warning {
  background: #d97706;
  border-color: #d97706;
}

.btn-danger {
  background: #dc2626;
  border-color: #dc2626;
}

.btn-sm {
  padding: 5px 12px;
  font-size: 13px;
}

.btn-outline-danger {
  color: #dc2626;
  border-color: #dc2626;
  background: transparent;
}

.btn-outline-danger:hover {
  background: #dc2626;
  color: #fff;
}

.btn-close {
  filter: none;
}

/* ---- Badges ---- */
.badge {
  font-weight: 500;
  font-size: 12px;
  padding: 3px 10px;
  border-radius: 6px;
}

.badge.bg-secondary {
  background: var(--badge-bg) !important;
  color: var(--badge-text);
}

.bg-secondary {
  background: var(--badge-bg) !important;
  color: var(--badge-text);
}

.badge-weak {
  background: #fee2e2;
  color: #dc2626;
}
.badge-strong {
  background: #dcfce7;
  color: #16a34a;
}
.badge-medium {
  background: #fef9c3;
  color: #ca8a04;
}

/* ---- Alerts ---- */
.alert {
  border-radius: 10px;
  border: 1px solid transparent;
  padding: 12px 16px;
  font-size: 14px;
}

.alert-info {
  background: var(--alert-info-bg);
  border-color: var(--alert-info-border);
  color: var(--alert-info-text);
}
.alert-success {
  background: var(--alert-success-bg);
  border-color: var(--alert-success-border);
  color: var(--alert-success-text);
}
.alert-danger {
  background: var(--alert-danger-bg);
  border-color: var(--alert-danger-border);
  color: var(--alert-danger-text);
}
.alert-warning {
  background: var(--alert-warning-bg);
  border-color: var(--alert-warning-border);
  color: var(--alert-warning-text);
}

/* ---- Progress bar ---- */
.progress {
  height: 8px;
  border-radius: 4px;
  background: var(--badge-bg);
  transition: background var(--transition-speed) ease;
}

.progress-bar {
  background: var(--brand-primary);
  border-radius: 4px;
}

/* ---- Breadcrumb ---- */
.breadcrumb {
  background: transparent;
  padding: 0;
  margin-bottom: 0;
  font-size: 13px;
}

.breadcrumb-item a {
  color: var(--brand-primary);
  text-decoration: none;
}

.breadcrumb-item a:hover {
  text-decoration: underline;
}

.breadcrumb-item.active {
  color: var(--text-muted);
}

.breadcrumb-item + .breadcrumb-item::before {
  color: var(--text-muted);
}

/* ---- Modal ---- */
.modal-content {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 14px;
  box-shadow: 0 8px 32px var(--modal-overlay);
  transition: background var(--transition-speed) ease, border-color var(--transition-speed) ease;
}

.modal-header {
  border-bottom: 1px solid var(--card-border);
  padding: 16px 20px;
  transition: border-color var(--transition-speed) ease;
}

.modal-footer {
  border-top: 1px solid var(--card-border);
  padding: 12px 20px;
  transition: border-color var(--transition-speed) ease;
}

.modal-backdrop.show {
  opacity: 0.5;
}

/* ---- List Group ---- */
.list-group-item {
  background: var(--card-bg);
  border-color: var(--card-border);
  color: var(--text-primary);
  transition: all var(--transition-speed) ease;
}

.list-group-item:hover {
  background: var(--table-hover-bg);
}

.list-group-item-action {
  color: var(--text-primary);
}

/* ---- Chart containers ---- */
.chart-container {
  min-height: 300px;
  position: relative;
}

/* ---- Watermark (from anti_leak) ---- */
#anti-leak-watermark {
  pointer-events: none !important;
  z-index: 999999 !important;
}

/* ---- WeChat Kefu ---- */
.kefu-btn {
  position: fixed;
  right: 10px;
  bottom: 100px;
  width: 35px;
  height: 35px;
  background: var(--kefu-bg);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 16px;
  cursor: pointer;
  box-shadow: 0 2px 12px rgba(0,0,0,.2);
  z-index: 9999;
  transition: transform var(--transition-speed) ease;
}

.kefu-btn:hover {
  transform: scale(1.1);
}

.kefu-modal {
  display: none;
  position: fixed;
  right: 10px;
  bottom: 145px;
  width: 150px;
  background: var(--card-bg);
  border-radius: 12px;
  box-shadow: 0 4px 20px var(--modal-overlay);
  z-index: 9998;
  padding: 20px;
  text-align: center;
  transition: background var(--transition-speed) ease;
}

.kefu-modal.show {
  display: block;
}

.kefu-modal img {
  width: 120px;
  height: 120px;
  border-radius: 8px;
}

.kefu-modal .close-btn {
  position: absolute;
  top: 8px;
  right: 12px;
  font-size: 20px;
  cursor: pointer;
  color: var(--text-muted);
  border: none;
  background: none;
}

.kefu-modal p {
  color: var(--text-primary) !important;
  font-size: 11px;
  margin-top: 8px;
  transition: color var(--transition-speed) ease;
}

/* ---- Misc ---- */
a {
  color: var(--brand-primary);
  text-decoration: none;
  transition: color var(--transition-speed) ease;
}

a:hover {
  color: var(--brand-primary-hover);
}

hr {
  border-color: var(--card-border);
  opacity: 1;
  transition: border-color var(--transition-speed) ease;
}

.text-muted {
  color: var(--text-muted) !important;
  transition: color var(--transition-speed) ease;
}

.text-primary {
  color: var(--brand-primary) !important;
}

.footer-text {
  color: var(--text-muted);
  font-size: 13px;
  transition: color var(--transition-speed) ease;
}

/* ---- Mobile Overlay ---- */
.sidebar-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--modal-overlay);
  z-index: 1025;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.sidebar-overlay.show {
  opacity: 1;
}

/* ---- Responsive ---- */
@media (max-width: 991.98px) {
  .sidebar-toggle-btn {
    display: block;
  }

  .sidebar {
    transform: translateX(-100%);
    transition: transform 0.3s ease;
    box-shadow: 4px 0 20px rgba(0,0,0,0.15);
  }

  .sidebar.open {
    transform: translateX(0);
  }

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

  .main-content {
    margin-left: 0;
  }

  .content-area {
    padding: 16px;
  }

  .topbar {
    padding: 10px 16px;
  }

  .topbar-user .user-name,
  .topbar-user .user-role {
    display: none;
  }
}

@media (max-width: 575.98px) {
  .content-area {
    padding: 12px;
  }

  .topbar {
    padding: 8px 12px;
    min-height: 52px;
  }

  .topbar-left .page-title {
    font-size: 15px;
  }

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

  .card-body {
    padding: 14px;
  }
}

/* Smooth scrollbar for main content */
.content-area::-webkit-scrollbar {
  width: 6px;
}

.content-area::-webkit-scrollbar-thumb {
  background: var(--scrollbar-thumb);
  border-radius: 3px;
}

.content-area::-webkit-scrollbar-track {
  background: transparent;
}