/* ============================================
   乾坤門大課堂 — XueZhengJun Style System
   Chinese Traditional Style / 中國風
   ============================================ */

/* --- Custom Properties --- */
:root {
  /* Primary palette */
  --color-red-deep: #8B0000;
  --color-red: #C41E3A;
  --color-red-light: #D4374A;
  --color-gold: #D4A574;
  --color-gold-dark: #B8860B;
  --color-gold-light: #E8C89E;

  /* Backgrounds */
  --color-bg-dark: #1a1a2e;
  --color-bg-navy: #16213e;
  --color-bg-cream: #f5f0e8;
  --color-bg-parchment: #faf6ef;
  --color-bg-white: #ffffff;

  /* Text */
  --color-text-primary: #2c2c2c;
  --color-text-secondary: #5a5a5a;
  --color-text-muted: #8a8a8a;
  --color-text-light: #e8e0d4;
  --color-text-gold: #D4A574;
  --color-text-white: #f5f0e8;

  /* Borders & Accents */
  --color-border: #d4c5a9;
  --color-border-light: #e8dcc8;
  --color-border-dark: #8B7355;
  --color-success: #2d7d46;
  --color-warning: #c48800;
  --color-danger: #c0392b;
  --color-info: #2874a6;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;

  /* Typography */
  --font-family: 'Noto Sans TC', 'Microsoft JhengHei', '微軟正黑體', 'PingFang TC', 'Heiti TC', sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 2rem;
  --font-size-4xl: 2.5rem;
  --font-size-5xl: 3.5rem;

  /* Borders */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.1);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
  --shadow-lg: 0 8px 30px rgba(0,0,0,0.15);
  --shadow-gold: 0 4px 20px rgba(212,165,116,0.2);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;

  /* Layout */
  --navbar-height: 64px;
  --sidebar-width: 260px;
  --container-max: 1200px;
}

/* --- Reset / Normalize --- */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: 1.7;
  color: var(--color-text-primary);
  background-color: var(--color-bg-parchment);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

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

a:hover {
  color: var(--color-red-deep);
}

ul, ol {
  list-style: none;
}

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

h1, h2, h3, h4, h5, h6 {
  line-height: 1.3;
  color: var(--color-text-primary);
  font-weight: 700;
}

h1 { font-size: var(--font-size-4xl); }
h2 { font-size: var(--font-size-3xl); }
h3 { font-size: var(--font-size-2xl); }
h4 { font-size: var(--font-size-xl); }
h5 { font-size: var(--font-size-lg); }

/* --- Layout Utilities --- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

.container-narrow {
  max-width: 720px;
}

.container-wide {
  max-width: 1400px;
}

.grid {
  display: grid;
  gap: var(--space-lg);
}

.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

.flex {
  display: flex;
}

.flex-center {
  display: flex;
  align-items: center;
  justify-content: center;
}

.flex-between {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.flex-col {
  flex-direction: column;
}

.flex-wrap {
  flex-wrap: wrap;
}

.gap-sm { gap: var(--space-sm); }
.gap-md { gap: var(--space-md); }
.gap-lg { gap: var(--space-lg); }
.gap-xl { gap: var(--space-xl); }

.text-center { text-align: center; }
.text-right { text-align: right; }

.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mt-xl { margin-top: var(--space-xl); }
.mt-2xl { margin-top: var(--space-2xl); }
.mb-sm { margin-bottom: var(--space-sm); }
.mb-md { margin-bottom: var(--space-md); }
.mb-lg { margin-bottom: var(--space-lg); }
.mb-xl { margin-bottom: var(--space-xl); }
.mb-2xl { margin-bottom: var(--space-2xl); }

.pt-xl { padding-top: var(--space-xl); }
.pb-xl { padding-bottom: var(--space-xl); }
.py-xl { padding-top: var(--space-xl); padding-bottom: var(--space-xl); }
.py-2xl { padding-top: var(--space-2xl); padding-bottom: var(--space-2xl); }
.py-3xl { padding-top: var(--space-3xl); padding-bottom: var(--space-3xl); }

.hidden { display: none !important; }

.main-content {
  flex: 1;
  padding-top: var(--navbar-height);
}

/* --- Chinese Decorative Elements --- */
.chinese-border {
  border: 1px solid var(--color-border);
  position: relative;
}

.chinese-border::before {
  content: '';
  position: absolute;
  inset: 4px;
  border: 1px solid var(--color-border-light);
  pointer-events: none;
}

.chinese-corner {
  position: relative;
}

.chinese-corner::before,
.chinese-corner::after {
  content: '';
  position: absolute;
  width: 20px;
  height: 20px;
  border-color: var(--color-gold);
  border-style: solid;
}

.chinese-corner::before {
  top: -2px;
  left: -2px;
  border-width: 2px 0 0 2px;
}

.chinese-corner::after {
  bottom: -2px;
  right: -2px;
  border-width: 0 2px 2px 0;
}

.divider-chinese {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin: var(--space-xl) 0;
  color: var(--color-gold);
}

.divider-chinese::before,
.divider-chinese::after {
  content: '';
  flex: 1;
  height: 1px;
  background: linear-gradient(to right, transparent, var(--color-gold), transparent);
}

.section-dark {
  background-color: var(--color-bg-dark);
  color: var(--color-text-light);
}

.section-dark h2,
.section-dark h3 {
  color: var(--color-text-gold);
}

.section-cream {
  background-color: var(--color-bg-cream);
}

/* --- Navigation --- */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--navbar-height);
  background: var(--color-bg-dark);
  border-bottom: 2px solid var(--color-gold-dark);
  z-index: 1000;
  display: flex;
  align-items: center;
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  max-width: var(--container-max);
}

.navbar-brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  color: var(--color-gold) !important;
  font-size: var(--font-size-xl);
  font-weight: 700;
  letter-spacing: 2px;
  text-decoration: none;
  white-space: nowrap;
}

.navbar-brand .brand-icon {
  font-size: var(--font-size-2xl);
}

.navbar-nav {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

.navbar-nav a {
  color: var(--color-text-light);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  font-size: var(--font-size-sm);
  white-space: nowrap;
}

.navbar-nav a:hover,
.navbar-nav a.active {
  color: var(--color-gold);
  background: rgba(212, 165, 116, 0.1);
}

.navbar-actions {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.navbar-user {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  color: var(--color-text-light);
  cursor: pointer;
  position: relative;
  padding: var(--space-sm);
  border-radius: var(--radius-sm);
}

.navbar-user:hover {
  background: rgba(255,255,255,0.05);
}

.navbar-user .avatar {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--color-gold-dark);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-bg-dark);
  font-weight: 700;
  font-size: var(--font-size-sm);
}

.user-dropdown {
  display: none;
  position: absolute;
  top: 100%;
  right: 0;
  margin-top: var(--space-xs);
  background: var(--color-bg-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  min-width: 180px;
  overflow: hidden;
  z-index: 100;
}

.user-dropdown.show {
  display: block;
}

.user-dropdown a {
  display: block;
  padding: var(--space-sm) var(--space-lg);
  color: var(--color-text-primary);
  font-size: var(--font-size-sm);
  transition: background var(--transition-fast);
}

.user-dropdown a:hover {
  background: var(--color-bg-cream);
  color: var(--color-red);
}

.user-dropdown .dropdown-divider {
  border-top: 1px solid var(--color-border-light);
  margin: var(--space-xs) 0;
}

/* Hamburger menu */
.navbar-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--color-text-light);
  font-size: 1.5rem;
  cursor: pointer;
  padding: var(--space-sm);
  line-height: 1;
}

.navbar-toggle .bar {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text-light);
  margin: 5px 0;
  transition: all var(--transition-base);
  border-radius: 1px;
}

.navbar-toggle.active .bar:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.navbar-toggle.active .bar:nth-child(2) {
  opacity: 0;
}

.navbar-toggle.active .bar:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

.mobile-menu {
  display: none;
  position: fixed;
  top: var(--navbar-height);
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--color-bg-dark);
  z-index: 999;
  padding: var(--space-xl);
  overflow-y: auto;
}

.mobile-menu.show {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.mobile-menu a {
  display: block;
  color: var(--color-text-light);
  padding: var(--space-md);
  border-bottom: 1px solid rgba(255,255,255,0.05);
  font-size: var(--font-size-lg);
}

.mobile-menu a:hover,
.mobile-menu a.active {
  color: var(--color-gold);
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: 0.6rem 1.5rem;
  border: none;
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-base);
  text-decoration: none;
  line-height: 1.5;
  white-space: nowrap;
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
  min-height: 44px;
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-red) 0%, var(--color-red-deep) 100%);
  color: #fff;
  box-shadow: 0 2px 8px rgba(196, 30, 58, 0.3);
}

.btn-primary:hover {
  background: linear-gradient(135deg, var(--color-red-light) 0%, var(--color-red) 100%);
  box-shadow: 0 4px 16px rgba(196, 30, 58, 0.4);
  transform: translateY(-1px);
  color: #fff;
}

.btn-gold {
  background: linear-gradient(135deg, var(--color-gold) 0%, var(--color-gold-dark) 100%);
  color: var(--color-bg-dark);
  box-shadow: 0 2px 8px rgba(184, 134, 11, 0.3);
}

.btn-gold:hover {
  box-shadow: 0 4px 16px rgba(184, 134, 11, 0.4);
  transform: translateY(-1px);
  color: var(--color-bg-dark);
}

.btn-secondary {
  background: transparent;
  color: var(--color-gold);
  border: 1px solid var(--color-gold);
}

.btn-secondary:hover {
  background: rgba(212, 165, 116, 0.1);
  color: var(--color-gold-light);
}

.btn-outline {
  background: transparent;
  color: var(--color-red);
  border: 1px solid var(--color-red);
}

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

.btn-sm {
  padding: 0.35rem 0.9rem;
  font-size: var(--font-size-xs);
  min-height: 36px;
}

.btn-lg {
  padding: 0.8rem 2rem;
  font-size: var(--font-size-lg);
  min-height: 52px;
}

.btn-block {
  display: flex;
  width: 100%;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none !important;
}

/* --- Cards --- */
.card {
  background: var(--color-bg-white);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border-light);
  overflow: hidden;
  transition: all var(--transition-base);
}

.card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

.card-body {
  padding: var(--space-lg);
}

.card-header {
  padding: var(--space-lg);
  border-bottom: 1px solid var(--color-border-light);
  font-weight: 700;
}

.card-footer {
  padding: var(--space-md) var(--space-lg);
  border-top: 1px solid var(--color-border-light);
  background: var(--color-bg-cream);
}

/* Course card */
.course-card {
  background: var(--color-bg-white);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border-light);
  overflow: hidden;
  transition: all var(--transition-base);
  display: flex;
  flex-direction: column;
}

.course-card:hover {
  box-shadow: var(--shadow-gold);
  transform: translateY(-4px);
  border-color: var(--color-gold);
}

.course-card-cover {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  background: linear-gradient(135deg, var(--color-bg-dark) 0%, var(--color-bg-navy) 100%);
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}

.course-card-cover img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0;
  transition: opacity var(--transition-base);
}

.course-card-cover img.loaded {
  opacity: 1;
}

.course-card-cover .default-pattern {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-4xl);
  color: var(--color-gold);
  opacity: 0.3;
  background-image: url('../img/pattern.svg');
  background-size: 200px;
  background-repeat: repeat;
}

.course-card-body {
  padding: var(--space-lg);
  flex: 1;
  display: flex;
  flex-direction: column;
}

.course-card-title {
  font-size: var(--font-size-lg);
  font-weight: 700;
  margin-bottom: var(--space-sm);
  color: var(--color-text-primary);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.course-card-meta {
  display: flex;
  gap: var(--space-md);
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  margin-bottom: var(--space-md);
}

.course-card-price {
  margin-top: auto;
  padding-top: var(--space-md);
  border-top: 1px solid var(--color-border-light);
  display: flex;
  align-items: baseline;
  justify-content: space-between;
}

.price-original {
  text-decoration: line-through;
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
}

.price-current {
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--color-red);
}

.price-free {
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--color-success);
}

/* --- Forms --- */
.form-group {
  margin-bottom: var(--space-lg);
}

.form-label {
  display: block;
  margin-bottom: var(--space-sm);
  font-weight: 600;
  font-size: var(--font-size-sm);
  color: var(--color-text-primary);
}

.form-input,
.form-select,
.form-textarea {
  width: 100%;
  padding: 0.7rem 1rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-base);
  color: var(--color-text-primary);
  background: var(--color-bg-white);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  min-height: 44px;
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
  outline: none;
  border-color: var(--color-gold);
  box-shadow: 0 0 0 3px rgba(212, 165, 116, 0.15);
}

.form-textarea {
  min-height: 120px;
  resize: vertical;
}

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

.form-check {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  cursor: pointer;
}

.form-check input[type="checkbox"] {
  width: 18px;
  height: 18px;
  accent-color: var(--color-red);
}

.form-hint {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  margin-top: var(--space-xs);
}

.form-error {
  font-size: var(--font-size-xs);
  color: var(--color-danger);
  margin-top: var(--space-xs);
}

/* Auth form card */
.auth-card {
  max-width: 440px;
  margin: var(--space-3xl) auto;
  background: var(--color-bg-white);
  border-radius: var(--radius-xl);
  padding: var(--space-2xl);
  position: relative;
  border: 1px solid var(--color-border-light);
  box-shadow: var(--shadow-md);
}

.auth-card::before {
  content: '';
  position: absolute;
  inset: 6px;
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  pointer-events: none;
}

.auth-header {
  text-align: center;
  margin-bottom: var(--space-xl);
}

.auth-header .brand {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  color: var(--color-red-deep);
  margin-bottom: var(--space-sm);
}

.auth-header .subtitle {
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
}

.auth-links {
  text-align: center;
  margin-top: var(--space-lg);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.auth-links a {
  color: var(--color-red);
  font-weight: 600;
}

/* --- Video Player --- */
.video-container {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  background: #000;
  border-radius: var(--radius-md);
  overflow: hidden;
}

.video-container video {
  width: 100%;
  height: 100%;
  object-fit: contain;
}

/* 倍速選擇器 */
.speed-control {
  position: absolute;
  top: 10px;
  right: 10px;
  z-index: 20;
}
.speed-btn {
  background: rgba(0, 0, 0, 0.6);
  color: #fff;
  border: 1px solid rgba(255, 255, 255, 0.3);
  border-radius: 4px;
  padding: 4px 10px;
  font-size: 13px;
  cursor: pointer;
  transition: background 0.2s;
}
.speed-btn:hover {
  background: rgba(0, 0, 0, 0.85);
}
.speed-menu {
  display: none;
  position: absolute;
  top: 100%;
  right: 0;
  margin-top: 4px;
  background: rgba(0, 0, 0, 0.85);
  border-radius: 6px;
  overflow: hidden;
  min-width: 70px;
}
.speed-menu.open {
  display: block;
}
.speed-option {
  padding: 6px 14px;
  color: #ccc;
  font-size: 13px;
  cursor: pointer;
  text-align: center;
  white-space: nowrap;
  transition: background 0.15s, color 0.15s;
}
.speed-option:hover {
  background: rgba(255, 255, 255, 0.15);
  color: #fff;
}
.speed-option.active {
  color: var(--color-gold, #f5c842);
  font-weight: 600;
}

.video-preview-overlay {
  display: none;
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.8);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  z-index: 10;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-lg);
  color: #fff;
  text-align: center;
  padding: var(--space-xl);
}

.video-preview-overlay.show {
  display: flex;
}

.video-preview-overlay .overlay-icon {
  font-size: 3rem;
  color: var(--color-gold);
}

.video-preview-overlay h3 {
  color: var(--color-text-gold);
  font-size: var(--font-size-xl);
}

.video-preview-overlay p {
  color: var(--color-text-light);
  font-size: var(--font-size-sm);
  max-width: 360px;
}

/* --- Lesson Sidebar --- */
.lesson-layout {
  display: grid;
  grid-template-columns: 1fr 340px;
  gap: var(--space-xl);
  align-items: start;
}

.lesson-sidebar {
  background: var(--color-bg-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  overflow: hidden;
  max-height: calc(100vh - var(--navbar-height) - 2rem);
  overflow-y: auto;
  position: sticky;
  top: calc(var(--navbar-height) + 1rem);
}

.lesson-sidebar-header {
  padding: var(--space-md) var(--space-lg);
  background: var(--color-bg-dark);
  color: var(--color-text-gold);
  font-weight: 700;
  font-size: var(--font-size-sm);
  position: sticky;
  top: 0;
  z-index: 5;
}

.lesson-list-item {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-lg);
  border-bottom: 1px solid var(--color-border-light);
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: background var(--transition-fast);
  text-decoration: none;
}

.lesson-list-item:hover {
  background: var(--color-bg-cream);
  color: var(--color-text-primary);
}

.lesson-list-item.current {
  background: rgba(196, 30, 58, 0.05);
  color: var(--color-red);
  border-left: 3px solid var(--color-red);
  font-weight: 600;
}

.lesson-list-item.locked {
  opacity: 0.5;
  cursor: not-allowed;
}

.lesson-list-item .lesson-icon {
  width: 20px;
  text-align: center;
  flex-shrink: 0;
}

.lesson-list-item .lesson-title {
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.lesson-list-item .lesson-duration {
  color: var(--color-text-muted);
  font-size: var(--font-size-xs);
  flex-shrink: 0;
}

.lesson-chapter-title {
  padding: var(--space-sm) var(--space-lg);
  background: var(--color-bg-cream);
  font-weight: 700;
  font-size: var(--font-size-sm);
  color: var(--color-text-primary);
  border-bottom: 1px solid var(--color-border-light);
}

.lesson-nav {
  display: flex;
  gap: var(--space-md);
  margin-top: var(--space-lg);
}

/* --- Badge --- */
.badge {
  display: inline-block;
  padding: 0.15rem 0.55rem;
  font-size: var(--font-size-xs);
  font-weight: 600;
  border-radius: 999px;
  line-height: 1.5;
}

.badge-preview {
  background: var(--color-gold);
  color: var(--color-bg-dark);
}

.badge-free {
  background: var(--color-success);
  color: #fff;
}

.badge-published {
  background: var(--color-success);
  color: #fff;
}

.badge-draft {
  background: var(--color-text-muted);
  color: #fff;
}

.badge-archived {
  background: var(--color-border-dark);
  color: #fff;
}

/* --- Progress Bar --- */
.progress {
  width: 100%;
  height: 8px;
  background: var(--color-border-light);
  border-radius: 999px;
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  background: linear-gradient(90deg, var(--color-red) 0%, var(--color-gold) 100%);
  border-radius: 999px;
  transition: width var(--transition-slow);
}

.progress-text {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  margin-top: var(--space-xs);
}

/* --- Toast Notifications --- */
.toast-container {
  position: fixed;
  top: calc(var(--navbar-height) + var(--space-md));
  right: var(--space-md);
  z-index: 9999;
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  pointer-events: none;
}

.toast {
  pointer-events: auto;
  padding: var(--space-md) var(--space-lg);
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: #fff;
  box-shadow: var(--shadow-lg);
  transform: translateX(120%);
  transition: transform var(--transition-base);
  max-width: 360px;
}

.toast.show {
  transform: translateX(0);
}

.toast-success {
  background: var(--color-success);
}

.toast-error {
  background: var(--color-danger);
}

.toast-warning {
  background: var(--color-warning);
}

.toast-info {
  background: var(--color-info);
}

/* --- Hero Section --- */
.hero {
  background: linear-gradient(135deg, var(--color-bg-dark) 0%, var(--color-bg-navy) 50%, #1a1428 100%);
  color: var(--color-text-light);
  padding: var(--space-3xl) 0;
  text-align: center;
  position: relative;
  overflow: hidden;
  min-height: 480px;
  display: flex;
  align-items: center;
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image: url('../img/pattern.svg');
  background-size: 300px;
  background-repeat: repeat;
  opacity: 0.04;
}

.hero-content {
  position: relative;
  z-index: 1;
  width: 100%;
}

.hero h1 {
  font-size: var(--font-size-5xl);
  color: var(--color-gold);
  margin-bottom: var(--space-md);
  letter-spacing: 8px;
  text-shadow: 0 2px 20px rgba(212, 165, 116, 0.3);
}

.hero .subtitle {
  font-size: var(--font-size-xl);
  color: var(--color-text-light);
  opacity: 0.85;
  margin-bottom: var(--space-2xl);
  letter-spacing: 6px;
}

/* Stats section */
.stats-row {
  display: flex;
  justify-content: center;
  gap: var(--space-2xl);
  flex-wrap: wrap;
}

.stat-item {
  text-align: center;
}

.stat-number {
  font-size: var(--font-size-4xl);
  font-weight: 700;
  color: var(--color-gold);
  line-height: 1.2;
}

.stat-label {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin-top: var(--space-xs);
}

/* --- About Section --- */
.about-section {
  padding: var(--space-3xl) 0;
}

.about-section .section-title {
  text-align: center;
  margin-bottom: var(--space-2xl);
}

.about-section .section-title h2 {
  color: var(--color-red-deep);
}

/* --- Accordion --- */
.accordion {
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.accordion-item {
  border-bottom: 1px solid var(--color-border-light);
}

.accordion-item:last-child {
  border-bottom: none;
}

.accordion-header {
  padding: var(--space-md) var(--space-lg);
  background: var(--color-bg-cream);
  font-weight: 700;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  user-select: none;
  transition: background var(--transition-fast);
}

.accordion-header:hover {
  background: var(--color-border-light);
}

.accordion-header .arrow {
  transition: transform var(--transition-base);
  font-size: var(--font-size-sm);
}

.accordion-header.active .arrow {
  transform: rotate(180deg);
}

.accordion-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-slow) ease;
}

.accordion-body.show {
  max-height: 2000px;
}

/* --- Admin Layout --- */
.admin-wrapper {
  display: flex;
  min-height: 100vh;
  padding-top: var(--navbar-height);
}

.admin-sidebar {
  width: var(--sidebar-width);
  background: var(--color-bg-dark);
  border-right: 1px solid rgba(255,255,255,0.05);
  position: fixed;
  top: var(--navbar-height);
  left: 0;
  bottom: 0;
  overflow-y: auto;
  z-index: 100;
  transition: transform var(--transition-base);
}

.admin-sidebar-nav {
  padding: var(--space-md) 0;
}

.admin-sidebar-nav a {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md) var(--space-xl);
  color: var(--color-text-light);
  font-size: var(--font-size-sm);
  transition: all var(--transition-fast);
  border-left: 3px solid transparent;
}

.admin-sidebar-nav a:hover,
.admin-sidebar-nav a.active {
  background: rgba(212, 165, 116, 0.08);
  color: var(--color-gold);
  border-left-color: var(--color-gold);
}

.admin-sidebar-nav .nav-icon {
  width: 20px;
  text-align: center;
}

.admin-content {
  flex: 1;
  margin-left: var(--sidebar-width);
  padding: var(--space-xl);
  min-width: 0;
}

.admin-page-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-xl);
  flex-wrap: wrap;
  gap: var(--space-md);
}

.admin-page-header h1 {
  font-size: var(--font-size-2xl);
}

/* Admin stat cards */
.stat-cards {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-lg);
  margin-bottom: var(--space-xl);
}

.stat-card {
  background: var(--color-bg-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
}

.stat-card .stat-card-label {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
}

.stat-card .stat-card-value {
  font-size: var(--font-size-3xl);
  font-weight: 700;
  color: var(--color-text-primary);
}

.stat-card .stat-card-value.text-red { color: var(--color-red); }
.stat-card .stat-card-value.text-gold { color: var(--color-gold-dark); }
.stat-card .stat-card-value.text-success { color: var(--color-success); }

.stat-card-sub {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  margin-top: var(--space-xs);
}

/* --- Tables --- */
.table-wrapper {
  overflow-x: auto;
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  background: var(--color-bg-white);
}

.table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--font-size-sm);
}

.table th {
  background: var(--color-bg-cream);
  font-weight: 700;
  text-align: left;
  padding: var(--space-md) var(--space-lg);
  border-bottom: 2px solid var(--color-border);
  white-space: nowrap;
  color: var(--color-text-primary);
}

.table td {
  padding: var(--space-md) var(--space-lg);
  border-bottom: 1px solid var(--color-border-light);
  vertical-align: middle;
}

.table tbody tr:hover {
  background: rgba(245, 240, 232, 0.5);
}

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

.table .actions {
  display: flex;
  gap: var(--space-sm);
}

/* --- Sidebar toggle for admin mobile --- */
.admin-sidebar-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--color-text-light);
  padding: var(--space-sm);
  cursor: pointer;
  font-size: 1.2rem;
}

/* --- Footer --- */
.footer {
  background: var(--color-bg-dark);
  color: var(--color-text-light);
  padding: var(--space-2xl) 0 var(--space-lg);
  margin-top: auto;
  border-top: 2px solid var(--color-gold-dark);
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: start;
  gap: var(--space-xl);
  margin-bottom: var(--space-xl);
}

.footer-brand {
  font-size: var(--font-size-xl);
  color: var(--color-gold);
  font-weight: 700;
  letter-spacing: 2px;
  margin-bottom: var(--space-sm);
}

.footer-tagline {
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
}

.footer-links h4 {
  color: var(--color-gold);
  font-size: var(--font-size-sm);
  margin-bottom: var(--space-md);
  font-weight: 600;
}

.footer-links a {
  display: block;
  color: var(--color-text-light);
  font-size: var(--font-size-sm);
  padding: var(--space-xs) 0;
  opacity: 0.7;
  transition: opacity var(--transition-fast);
}

.footer-links a:hover {
  opacity: 1;
  color: var(--color-gold);
}

.footer-bottom {
  text-align: center;
  padding-top: var(--space-lg);
  border-top: 1px solid rgba(255,255,255,0.05);
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

/* --- Error Pages --- */
.error-page {
  min-height: calc(100vh - var(--navbar-height));
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--space-xl);
}

.error-code {
  font-size: 6rem;
  font-weight: 700;
  color: var(--color-gold);
  line-height: 1;
  margin-bottom: var(--space-md);
  text-shadow: 0 2px 20px rgba(212, 165, 116, 0.2);
}

.error-message {
  font-size: var(--font-size-2xl);
  color: var(--color-text-primary);
  margin-bottom: var(--space-md);
}

.error-description {
  color: var(--color-text-muted);
  margin-bottom: var(--space-xl);
}

/* --- Course Detail Page --- */
.course-header {
  background: linear-gradient(135deg, var(--color-bg-dark) 0%, var(--color-bg-navy) 100%);
  color: var(--color-text-light);
  padding: var(--space-2xl) 0;
}

.course-header-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-2xl);
  align-items: center;
}

.course-header-info h1 {
  color: var(--color-text-gold);
  font-size: var(--font-size-3xl);
  margin-bottom: var(--space-md);
}

.course-header-info .description {
  color: var(--color-text-light);
  opacity: 0.85;
  margin-bottom: var(--space-lg);
  line-height: 1.8;
}

.course-header-cover {
  border-radius: var(--radius-lg);
  overflow: hidden;
  aspect-ratio: 16 / 9;
  background: rgba(255,255,255,0.05);
}

.course-header-cover img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.course-price-box {
  display: flex;
  align-items: baseline;
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
}

.course-price-box .price-current {
  font-size: var(--font-size-3xl);
  color: var(--color-gold);
}

.course-price-box .price-original {
  color: var(--color-text-muted);
}

.course-stats-sidebar {
  background: var(--color-bg-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
}

.course-stat-row {
  display: flex;
  justify-content: space-between;
  padding: var(--space-sm) 0;
  border-bottom: 1px solid var(--color-border-light);
  font-size: var(--font-size-sm);
}

.course-stat-row:last-child {
  border-bottom: none;
}

.course-stat-row .label {
  color: var(--color-text-muted);
}

.course-stat-row .value {
  font-weight: 600;
}

/* --- Dashboard --- */
.dashboard-welcome {
  margin-bottom: var(--space-xl);
}

.dashboard-welcome h1 {
  font-size: var(--font-size-2xl);
  color: var(--color-text-primary);
}

.dashboard-welcome p {
  color: var(--color-text-muted);
}

.course-progress-card {
  background: var(--color-bg-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: all var(--transition-base);
}

.course-progress-card:hover {
  box-shadow: var(--shadow-md);
}

.course-progress-card .card-cover {
  aspect-ratio: 16 / 9;
  background: var(--color-bg-dark);
  overflow: hidden;
}

.course-progress-card .card-cover img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.course-progress-card .card-info {
  padding: var(--space-lg);
  flex: 1;
}

.course-progress-card .card-info h3 {
  font-size: var(--font-size-lg);
  margin-bottom: var(--space-sm);
}

/* --- Search / Filter bar --- */
.filter-bar {
  display: flex;
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
  flex-wrap: wrap;
}

.filter-bar .form-input {
  max-width: 300px;
}

/* --- Responsive --- */
@media (max-width: 1024px) {
  .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }

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

  .lesson-layout {
    grid-template-columns: 1fr;
  }

  .lesson-sidebar {
    position: static;
    max-height: none;
  }

  .course-header-inner {
    grid-template-columns: 1fr;
  }

  .course-header-cover {
    max-width: 560px;
  }

  .footer-content {
    flex-direction: column;
  }
}

@media (max-width: 768px) {
  :root {
    --navbar-height: 56px;
  }

  .navbar-nav {
    display: none;
  }

  .navbar-actions {
    display: none;
  }

  .navbar-toggle {
    display: block;
  }

  .grid-2 {
    grid-template-columns: 1fr;
  }

  .grid-3 {
    grid-template-columns: 1fr;
  }

  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }

  .stat-cards {
    grid-template-columns: 1fr 1fr;
  }

  .hero h1 {
    font-size: var(--font-size-3xl);
    letter-spacing: 4px;
  }

  .hero .subtitle {
    font-size: var(--font-size-lg);
    letter-spacing: 3px;
  }

  .stats-row {
    gap: var(--space-lg);
  }

  .stat-number {
    font-size: var(--font-size-2xl);
  }

  /* Admin sidebar collapse */
  .admin-sidebar {
    transform: translateX(-100%);
  }

  .admin-sidebar.show {
    transform: translateX(0);
  }

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

  .admin-sidebar-toggle {
    display: block;
  }

  .auth-card {
    margin: var(--space-xl) var(--space-md);
    padding: var(--space-xl);
  }

  .table {
    font-size: var(--font-size-xs);
  }

  .table th,
  .table td {
    padding: var(--space-sm) var(--space-md);
  }

  h1 { font-size: var(--font-size-2xl); }
  h2 { font-size: var(--font-size-xl); }
}

@media (max-width: 480px) {
  .grid-4 {
    grid-template-columns: 1fr;
  }

  .stat-cards {
    grid-template-columns: 1fr;
  }

  .course-card-meta {
    flex-direction: column;
    gap: var(--space-xs);
  }

  .hero {
    padding: var(--space-2xl) 0;
    min-height: 380px;
  }

  .hero h1 {
    font-size: var(--font-size-2xl);
  }

  .btn-lg {
    padding: 0.7rem 1.5rem;
    font-size: var(--font-size-base);
  }

  .container {
    padding: 0 var(--space-md);
  }

  .filter-bar .form-input {
    max-width: 100%;
    width: 100%;
  }
}

/* ============================================
   Admin Course Management — 圖片上傳 / 章節 / 課時
   ============================================ */

/* Image upload zone */
.image-upload-zone {
  border: 2px dashed var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  text-align: center;
  cursor: pointer;
  transition: all var(--transition-fast);
  min-height: 160px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-bg-parchment);
}

.image-upload-zone:hover {
  border-color: var(--color-gold);
  background: rgba(212, 165, 116, 0.05);
}

.image-upload-zone .image-preview {
  max-width: 100%;
  max-height: 200px;
  object-fit: contain;
  border-radius: var(--radius-sm);
}

.upload-placeholder {
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
}

/* VOD upload zone */
.vod-upload-zone {
  border: 2px dashed var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  text-align: center;
  cursor: pointer;
  transition: all var(--transition-fast);
  background: var(--color-bg-parchment);
}

.vod-upload-zone:hover,
.vod-upload-zone.dragover {
  border-color: var(--color-gold);
  background: rgba(212, 165, 116, 0.08);
}

.progress-bar-wrapper {
  width: 100%;
  height: 8px;
  background: var(--color-border-light);
  border-radius: 4px;
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  background: var(--color-gold-dark);
  border-radius: 4px;
  transition: width 0.3s ease;
}

/* Chapter list */
.chapter-list {
  /* no extra padding; items fill card body */
}

.chapter-item {
  border-bottom: 1px solid var(--color-border-light);
}

.chapter-item:last-child {
  border-bottom: none;
}

.chapter-header {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md) var(--space-lg);
  background: var(--color-bg-cream);
  font-weight: 700;
  font-size: var(--font-size-sm);
}

.chapter-title {
  flex: 1;
}

.chapter-actions {
  display: flex;
  gap: var(--space-xs);
  flex-shrink: 0;
}

/* Lesson list */
.lesson-list {
  padding-left: 0;
}

.lesson-item {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-sm) var(--space-lg) var(--space-sm) calc(var(--space-lg) + 24px);
  border-bottom: 1px solid var(--color-border-light);
  font-size: var(--font-size-sm);
}

.lesson-item:last-child {
  border-bottom: none;
}

.lesson-item:hover {
  background: rgba(245, 240, 232, 0.5);
}

.lesson-title {
  flex: 1;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.lesson-meta {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  color: var(--color-text-muted);
  font-size: var(--font-size-xs);
  flex-shrink: 0;
}

.lesson-actions {
  display: flex;
  gap: var(--space-xs);
  flex-shrink: 0;
}

.lesson-empty {
  padding: var(--space-md) var(--space-lg) var(--space-md) calc(var(--space-lg) + 24px);
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  font-style: italic;
}

/* Drag handle */
.drag-handle {
  cursor: grab;
  color: var(--color-text-muted);
  font-size: 1rem;
  user-select: none;
  flex-shrink: 0;
  width: 20px;
  text-align: center;
}

.drag-handle:active {
  cursor: grabbing;
}

/* Alert messages */
.alert {
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-sm);
  margin-bottom: var(--space-lg);
  font-size: var(--font-size-sm);
}

.alert-success {
  background: var(--color-success);
  color: #fff;
}

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

/* Badge variants */
.badge-free {
  background: var(--color-info);
  color: #fff;
  font-size: var(--font-size-xs);
  padding: 1px 6px;
  border-radius: var(--radius-sm);
}

/* Extra small buttons */
.btn-xs {
  padding: 2px 8px;
  font-size: var(--font-size-xs);
  border-radius: var(--radius-sm);
}

.btn-danger {
  background: var(--color-danger);
  color: #fff;
  border: 1px solid var(--color-danger);
}

.btn-danger:hover {
  background: #a93226;
}

.text-danger {
  color: var(--color-danger);
}

/* Checkbox label */
.checkbox-label {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  cursor: pointer;
  font-size: var(--font-size-sm);
  padding-top: var(--space-md);
}

.checkbox-label input[type="checkbox"] {
  width: 18px;
  height: 18px;
  cursor: pointer;
}

/* Form input small */
.form-input-sm {
  padding: var(--space-xs) var(--space-sm);
  font-size: var(--font-size-sm);
}

/* --- Course Detail Extracted --- */
.course-header-text {
  max-width: 800px;
}

.course-badge-preview {
  background: var(--color-gold);
  color: var(--color-bg-dark);
  padding: 4px 12px;
  border-radius: 4px;
  font-size: var(--font-size-xs);
  font-weight: 700;
  display: inline-block;
  margin-bottom: var(--space-sm);
}

.course-detail-title {
  font-size: var(--font-size-3xl);
  margin-bottom: var(--space-md);
  color: #fff;
}

.course-desc {
  opacity: 0.9;
  line-height: 1.8;
  margin-bottom: var(--space-xl);
  color: #f5f0e8;
}

.course-desc h1,
.course-desc h2,
.course-desc h3,
.course-desc p,
.course-desc span {
  color: #f5f0e8 !important;
}

.course-desc a {
  color: var(--color-gold) !important;
  text-decoration: underline;
}

.course-detail-pricing {
  display: flex;
  align-items: center;
  gap: var(--space-xl);
  flex-wrap: wrap;
  margin-bottom: var(--space-xl);
}

.course-detail-original {
  text-decoration: line-through;
  opacity: 0.5;
  margin-right: 8px;
}

.course-detail-sale {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  color: var(--color-gold);
}

.course-detail-meta {
  display: flex;
  gap: var(--space-lg);
  opacity: 0.7;
  font-size: var(--font-size-sm);
}

.course-detail-progress {
  margin-left: var(--space-md);
  opacity: 0.7;
}

.course-outline-title {
  font-size: var(--font-size-xl);
}

/* Accordion items in course detail (override generic .accordion-item) */
.course-accordion .accordion-item {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-sm);
  overflow: hidden;
}

.course-accordion .accordion-header {
  background: var(--color-surface, var(--color-bg-cream));
  padding: var(--space-md) var(--space-lg);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: 600;
}

.accordion-lesson-count {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

.lesson-row {
  display: flex;
  align-items: center;
  padding: var(--space-sm) var(--space-lg);
  text-decoration: none;
  color: inherit;
  border-top: 1px solid var(--color-border);
  gap: var(--space-md);
  transition: background 0.2s;
}

.lesson-row:hover {
  background: var(--color-bg-cream);
}

.lesson-row-icon {
  width: 24px;
  text-align: center;
  flex-shrink: 0;
}

.lesson-row-title {
  flex: 1;
}

.lesson-row-badge {
  background: var(--color-gold);
  color: var(--color-bg-dark);
  padding: 1px 6px;
  border-radius: 3px;
  font-size: 11px;
  margin-left: 6px;
}

.lesson-row-duration {
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  flex-shrink: 0;
}

/* --- Lesson Page Extracted --- */
.lesson-info {
  margin-top: var(--space-xl);
}

.lesson-page-title {
  font-size: var(--font-size-2xl);
  margin-bottom: var(--space-sm);
}

.lesson-page-meta {
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
}

.lesson-nav-row {
  margin-top: var(--space-lg);
  display: flex;
  justify-content: space-between;
  gap: 1rem;
}

.lesson-locked-placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100%;
  background: var(--color-bg-dark);
  color: #fff;
  flex-direction: column;
  gap: 1rem;
}

.lesson-locked-icon {
  font-size: 3rem;
}

.lesson-chapter-header {
  padding: var(--space-sm) var(--space-md);
  background: var(--color-bg-cream);
  font-weight: 600;
  font-size: var(--font-size-sm);
}

.lesson-sidebar-item {
  display: flex;
  align-items: center;
  padding: var(--space-xs) var(--space-md);
  text-decoration: none;
  color: inherit;
  gap: var(--space-sm);
  font-size: var(--font-size-sm);
  border-bottom: 1px solid var(--color-border);
  transition: background var(--transition-fast);
}

.lesson-sidebar-item:hover {
  background: var(--color-bg-cream);
}

.lesson-sidebar-item.current {
  background: rgba(196, 30, 58, 0.05);
  font-weight: 600;
}

.lesson-sidebar-icon {
  width: 18px;
  text-align: center;
  flex-shrink: 0;
}

.lesson-sidebar-title {
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.lesson-sidebar-duration {
  color: var(--color-text-muted);
  font-size: 11px;
  flex-shrink: 0;
}

/* --- Checkout Page --- */
.checkout-order-summary {
  display: flex;
  gap: var(--space-lg);
  align-items: start;
}

.checkout-cover {
  width: 120px;
  height: 80px;
  object-fit: cover;
  border-radius: var(--radius-sm);
  flex-shrink: 0;
}

.checkout-info {
  flex: 1;
  min-width: 0;
}

.checkout-info h3 {
  margin: 0 0 var(--space-sm) 0;
  font-size: var(--font-size-lg);
}

.checkout-info-sub {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.checkout-price-col {
  text-align: right;
  white-space: nowrap;
}

.checkout-price-original {
  text-decoration: line-through;
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
}

.checkout-price-final {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  color: var(--color-red);
}

.checkout-method-label {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md) var(--space-lg);
  border-bottom: 1px solid var(--color-border-light);
  cursor: pointer;
  transition: background .15s;
}

.checkout-method-label:hover {
  background: rgba(245,240,232,0.5);
}

.checkout-method-label:last-child {
  border-bottom: none;
}

.checkout-method-radio {
  width: 18px;
  height: 18px;
  accent-color: var(--color-red);
}

.checkout-method-icon {
  font-size: 1.2rem;
}

.checkout-method-name {
  flex: 1;
  font-weight: 500;
}

.checkout-method-price {
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
}

.checkout-footer {
  display: flex;
  gap: var(--space-md);
  justify-content: space-between;
  align-items: center;
}

.checkout-back {
  color: var(--color-text-muted);
  text-decoration: none;
}

.checkout-pay-btn {
  padding: var(--space-md) var(--space-2xl);
  font-size: var(--font-size-lg);
}

@media (max-width: 480px) {
  .checkout-order-summary {
    flex-direction: column;
  }

  .checkout-cover {
    width: 100%;
    height: auto;
    aspect-ratio: 16 / 9;
  }

  .checkout-price-col {
    text-align: left;
  }

  .checkout-footer {
    flex-direction: column-reverse;
    gap: var(--space-md);
  }

  .checkout-pay-btn {
    width: 100%;
  }
}

/* --- Lesson sidebar mobile toggle --- */
.lesson-sidebar-toggle {
  display: none;
  width: 100%;
  padding: var(--space-md);
  background: var(--color-bg-dark);
  color: var(--color-text-gold);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  font-weight: 700;
  font-size: var(--font-size-sm);
  cursor: pointer;
  text-align: left;
}

.lesson-sidebar-toggle::after {
  content: '▼';
  float: right;
  transition: transform var(--transition-base);
}

.lesson-sidebar-toggle.expanded::after {
  transform: rotate(180deg);
}

@media (max-width: 1024px) {
  .lesson-sidebar-toggle {
    display: block;
  }

  .lesson-sidebar.collapsed {
    display: none;
  }
}

/* --- Homework Section --- */
.homework-section {
  margin-top: var(--space-2xl);
  padding: var(--space-xl);
  background: var(--color-bg-white);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
}

.homework-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-lg);
  padding-bottom: var(--space-md);
  border-bottom: 2px solid var(--color-gold);
}

.homework-header h3 {
  font-size: var(--font-size-xl);
  color: var(--color-text-primary);
  margin: 0;
}

.homework-instructions {
  background: var(--color-bg-cream);
  padding: var(--space-md) var(--space-lg);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-lg);
  font-size: var(--font-size-sm);
  line-height: 1.8;
  border-left: 3px solid var(--color-gold);
}

.homework-file-zone {
  border: 2px dashed var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  text-align: center;
  cursor: pointer;
  transition: all var(--transition-fast);
  background: var(--color-bg-parchment);
}

.homework-file-zone:hover,
.homework-file-zone.dragover {
  border-color: var(--color-gold);
  background: rgba(212, 165, 116, 0.05);
}

.homework-file-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
  margin-top: var(--space-sm);
}

.homework-file-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-sm) var(--space-md);
  background: var(--color-bg-cream);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
  text-decoration: none;
  color: inherit;
}

.homework-file-item:hover {
  background: var(--color-border-light);
}

.homework-content-display {
  background: var(--color-bg-cream);
  padding: var(--space-md) var(--space-lg);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-lg);
  font-size: var(--font-size-sm);
  line-height: 1.8;
}

.homework-files-display {
  margin-bottom: var(--space-lg);
  font-size: var(--font-size-sm);
}

.homework-feedback {
  padding: var(--space-md) var(--space-lg);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-md);
  font-size: var(--font-size-sm);
  line-height: 1.8;
}

.homework-feedback-ai {
  background: rgba(40, 116, 166, 0.08);
  border-left: 3px solid var(--color-info);
}

.homework-feedback-teacher {
  background: rgba(212, 165, 116, 0.1);
  border-left: 3px solid var(--color-gold);
}

.homework-feedback-label {
  font-weight: 700;
  margin-bottom: var(--space-sm);
  font-size: var(--font-size-sm);
}

.homework-feedback-ai .homework-feedback-label {
  color: var(--color-info);
}

.homework-feedback-teacher .homework-feedback-label {
  color: var(--color-gold-dark);
}

/* --- AI Q&A Chat Widget --- */
.qa-fab {
  position: fixed;
  bottom: 24px;
  right: 24px;
  height: 48px;
  padding: 0 20px 0 16px;
  border-radius: 24px;
  background: linear-gradient(135deg, var(--color-gold) 0%, var(--color-gold-dark) 100%);
  color: var(--color-bg-dark);
  border: none;
  cursor: pointer;
  box-shadow: 0 4px 20px rgba(196, 168, 100, 0.5);
  z-index: 900;
  display: flex;
  align-items: center;
  gap: 6px;
  transition: all var(--transition-base);
  font-weight: 700;
  font-size: var(--font-size-sm);
  animation: qa-fab-pulse 2s ease-in-out 3;
}

@keyframes qa-fab-pulse {
  0%, 100% { transform: scale(1); box-shadow: 0 4px 20px rgba(196, 168, 100, 0.5); }
  50% { transform: scale(1.08); box-shadow: 0 6px 30px rgba(196, 168, 100, 0.7); }
}

.qa-fab:hover {
  transform: scale(1.08);
  box-shadow: 0 6px 28px rgba(196, 168, 100, 0.7);
}

.qa-fab-icon {
  font-size: 1.3rem;
}

.qa-fab-label {
  letter-spacing: 0.5px;
}

.qa-panel {
  display: none;
  position: fixed;
  bottom: 92px;
  right: 24px;
  width: 380px;
  max-height: 520px;
  background: var(--color-bg-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-lg);
  z-index: 901;
  flex-direction: column;
  overflow: hidden;
}

.qa-panel.show {
  display: flex;
}

.qa-panel-header {
  padding: var(--space-md) var(--space-lg);
  background: var(--color-bg-dark);
  color: var(--color-text-gold);
  font-weight: 700;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.qa-panel-close {
  background: none;
  border: none;
  color: var(--color-text-light);
  font-size: 1.4rem;
  cursor: pointer;
  padding: 0;
  line-height: 1;
}

.qa-panel-close:hover {
  color: var(--color-gold);
}

.qa-messages {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-md);
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  min-height: 300px;
  max-height: 380px;
}

.qa-msg {
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  line-height: 1.6;
  max-width: 88%;
  word-break: break-word;
  white-space: pre-wrap;
}

.qa-msg-user {
  background: linear-gradient(135deg, var(--color-red) 0%, var(--color-red-deep) 100%);
  color: #fff;
  align-self: flex-end;
  border-bottom-right-radius: 4px;
}

.qa-msg-bot {
  background: var(--color-bg-cream);
  color: var(--color-text-primary);
  align-self: flex-start;
  border-bottom-left-radius: 4px;
}

.qa-msg-bot.qa-error {
  background: rgba(192, 57, 43, 0.1);
  color: var(--color-danger);
}

.qa-msg-bot.qa-thinking {
  color: var(--color-text-muted);
  font-style: italic;
}

.qa-input-area {
  display: flex;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  border-top: 1px solid var(--color-border-light);
  background: var(--color-bg-parchment);
}

.qa-input {
  flex: 1;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: var(--space-sm) var(--space-md);
  font-size: var(--font-size-sm);
  min-height: 40px;
}

.qa-input:focus {
  outline: none;
  border-color: var(--color-gold);
}

.qa-send-btn {
  background: var(--color-red);
  color: #fff;
  border: none;
  border-radius: var(--radius-sm);
  padding: var(--space-sm) var(--space-md);
  font-size: var(--font-size-sm);
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
  min-height: 40px;
}

.qa-send-btn:hover {
  background: var(--color-red-deep);
}

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

@media (max-width: 480px) {
  .qa-panel {
    right: 8px;
    left: 8px;
    bottom: 84px;
    width: auto;
  }

  .qa-fab {
    bottom: 16px;
    right: 16px;
  }
}

/* --- QA Balance Badge --- */
.qa-balance {
  font-size: var(--font-size-xs);
  background: rgba(255,255,255,0.15);
  padding: 2px 10px;
  border-radius: 12px;
  color: var(--color-gold-light);
  white-space: nowrap;
}
.qa-balance.low {
  background: rgba(255,80,80,0.3);
  color: #ff6b6b;
  animation: qa-balance-blink 1.5s ease-in-out infinite;
}
@keyframes qa-balance-blink {
  0%,100% { opacity: 1; }
  50% { opacity: 0.5; }
}

/* --- QA Streaming Dots --- */
.qa-dots::after {
  content: '...';
  animation: qa-dots-anim 1.2s steps(4, end) infinite;
}
@keyframes qa-dots-anim {
  0% { content: ''; }
  25% { content: '.'; }
  50% { content: '..'; }
  75% { content: '...'; }
}
.qa-streaming { min-height: 1.5em; }

/* --- QA Bot Message Formatting --- */
.qa-msg-bot h3, .qa-msg-bot h4 {
  margin: 0.5em 0 0.3em; font-size: 1em; color: var(--color-gold);
}
.qa-msg-bot ul { margin: 0.3em 0; padding-left: 1.2em; }
.qa-msg-bot li { margin: 0.15em 0; }
.qa-msg-bot code {
  background: rgba(0,0,0,0.3); padding: 1px 5px; border-radius: 3px;
  font-size: 0.9em;
}
.qa-msg-bot pre {
  background: rgba(0,0,0,0.3); padding: 8px 12px; border-radius: 6px;
  overflow-x: auto; margin: 0.4em 0; font-size: 0.85em;
}
.qa-msg-bot strong { color: var(--color-gold); }

/* --- QA Inline Chat (Lesson Page) --- */
.qa-inline {
  margin-top: var(--space-xl);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--color-bg-card);
}
.qa-inline-header {
  padding: var(--space-md) var(--space-lg);
  background: var(--color-bg-dark);
  color: var(--color-text-gold);
  font-weight: 700;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.qa-inline-title { font-size: var(--font-size-base); }
.qa-inline-messages {
  height: 360px;
  overflow-y: auto;
  padding: var(--space-md);
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  background: var(--color-bg-section);
}
.qa-inline-input-area {
  padding: var(--space-md);
  border-top: 1px solid var(--color-border-light);
  display: flex;
  gap: var(--space-sm);
  background: var(--color-bg-card);
}
.qa-inline-input-area .qa-input {
  flex: 1;
  padding: var(--space-sm) var(--space-md);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-bg-white);
  color: var(--color-text-primary);
  font-size: var(--font-size-sm);
}
.qa-inline-input-area .qa-send-btn {
  padding: var(--space-sm) var(--space-lg);
  background: linear-gradient(135deg, var(--color-gold) 0%, var(--color-gold-dark) 100%);
  color: var(--color-bg-dark);
  border: none;
  border-radius: var(--radius-md);
  font-weight: 700;
  cursor: pointer;
  transition: all var(--transition-base);
}
.qa-inline-input-area .qa-send-btn:hover {
  transform: scale(1.03);
}
.qa-inline-input-area .qa-send-btn:disabled {
  opacity: 0.5; cursor: not-allowed;
}

@media (max-width: 768px) {
  .qa-inline-messages { height: 280px; }
}

/* --- System Settings Page --- */
.settings-tabs {
  display: flex;
  gap: 0;
  margin-bottom: var(--space-xl);
  border-bottom: 2px solid var(--color-border-light);
}

.settings-tab {
  padding: var(--space-md) var(--space-lg);
  text-decoration: none;
  color: var(--color-text-muted);
  font-weight: 500;
  font-size: var(--font-size-sm);
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.settings-tab:hover {
  color: var(--color-text-primary);
  background: rgba(245, 240, 232, 0.5);
}

.settings-tab.active {
  color: var(--color-red);
  border-bottom-color: var(--color-red);
  font-weight: 700;
}

.tab-icon {
  font-size: var(--font-size-base);
}

.settings-info-row {
  display: flex;
  align-items: center;
  padding: var(--space-sm) 0;
  border-bottom: 1px solid var(--color-border-light);
}

.settings-info-row:last-child {
  border-bottom: none;
}

.settings-label {
  width: 160px;
  flex-shrink: 0;
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
}

.settings-value {
  flex: 1;
  font-size: var(--font-size-sm);
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  flex-wrap: wrap;
}

.settings-value code {
  background: var(--color-bg-cream);
  padding: 1px 6px;
  border-radius: var(--radius-sm);
  font-size: var(--font-size-xs);
  color: var(--color-red-deep);
}

/* LLM Provider Cards */
.llm-provider-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--space-lg);
}

.llm-provider-card {
  border: 2px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  cursor: pointer;
  transition: all var(--transition-fast);
  background: var(--color-bg-white);
  position: relative;
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.llm-provider-card:hover {
  border-color: var(--color-gold);
  box-shadow: var(--shadow-md);
}

.llm-provider-card.selected {
  border-color: var(--color-red);
  box-shadow: 0 0 0 1px var(--color-red), var(--shadow-md);
  background: rgba(196, 30, 58, 0.02);
}

.llm-provider-card input[type="radio"] {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.llm-provider-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.llm-provider-name {
  font-weight: 700;
  font-size: var(--font-size-lg);
  color: var(--color-text-primary);
}

.llm-provider-detail {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

.llm-provider-detail code {
  background: var(--color-bg-cream);
  padding: 1px 6px;
  border-radius: var(--radius-sm);
  font-size: var(--font-size-xs);
  color: var(--color-red-deep);
}

.llm-test-btn {
  align-self: flex-start;
}

.llm-test-result {
  font-size: var(--font-size-xs);
  padding: var(--space-xs) 0;
  min-height: 1.2em;
}

.llm-test-result.success {
  color: var(--color-success);
}

.llm-test-result.error {
  color: var(--color-danger);
}

/* Badges */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  font-size: var(--font-size-xs);
  font-weight: 600;
  line-height: 1.4;
}

.badge-success {
  background: var(--color-success);
  color: #fff;
}

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

.badge-warning {
  background: var(--color-warning);
  color: #fff;
}

.badge-outline {
  background: transparent;
  border: 1px solid var(--color-border);
  color: var(--color-text-secondary);
}

/* Progress bar fill variant */
.progress-bar-fill {
  height: 100%;
  background: var(--color-success);
  border-radius: 4px;
  transition: width 0.3s ease;
}

.progress-bar-fill.warning {
  background: var(--color-warning);
}

.progress-bar-fill.danger {
  background: var(--color-danger);
}

@media (max-width: 768px) {
  .settings-tabs {
    flex-wrap: wrap;
  }

  .settings-tab {
    padding: var(--space-sm) var(--space-md);
    font-size: var(--font-size-xs);
  }

  .settings-label {
    width: 120px;
  }

  .llm-provider-grid {
    grid-template-columns: 1fr;
  }

  .settings-info-row {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-xs);
  }
}

/* --- Email Compose Page --- */
.grid-email-compose {
  display: grid;
  grid-template-columns: 1fr 380px;
}

.email-recipient-info {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

.email-recipient-count {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  color: var(--color-red);
}

.email-toolbar {
  display: flex;
  gap: 2px;
  padding: var(--space-xs);
  background: var(--color-bg-cream);
  border: 1px solid var(--color-border);
  border-bottom: none;
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
}

.email-tb-btn {
  padding: 4px 10px;
  border: 1px solid var(--color-border-light);
  background: var(--color-bg-white);
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: var(--font-size-xs);
  transition: all var(--transition-fast);
}

.email-tb-btn:hover {
  background: var(--color-bg-parchment);
  border-color: var(--color-gold);
}

.email-toolbar-sep {
  width: 1px;
  background: var(--color-border);
  margin: 0 var(--space-xs);
}

.email-body-input {
  border-radius: 0 0 var(--radius-sm) var(--radius-sm);
  font-family: monospace;
  font-size: var(--font-size-sm);
  line-height: 1.6;
  resize: vertical;
}

.email-action-bar {
  display: flex;
  justify-content: flex-end;
  gap: var(--space-md);
}

/* Email Preview */
.email-preview-frame {
  max-height: 600px;
  overflow-y: auto;
}

.email-preview-placeholder {
  padding: var(--space-2xl);
  text-align: center;
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
}

.email-preview-inner {
  font-size: var(--font-size-sm);
}

.email-preview-header {
  background: #8B0000;
  color: #D4A574;
  padding: 16px;
  text-align: center;
  font-size: var(--font-size-lg);
  font-weight: 700;
}

.email-preview-body {
  padding: 20px;
  background: #f5f0e8;
  color: #2c2c2c;
  line-height: 1.8;
}

.email-preview-subject {
  font-size: var(--font-size-base);
  font-weight: 700;
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-sm);
  border-bottom: 1px solid var(--color-border);
}

.email-preview-content {
  font-size: var(--font-size-sm);
  word-break: break-word;
}

.email-preview-content a {
  color: #C41E3A;
  font-weight: 600;
}

.email-preview-footer {
  background: #1a1a2e;
  color: #888;
  padding: 12px;
  text-align: center;
  font-size: 11px;
}

/* Send Dialog Overlay */
.email-send-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.6);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
}

.email-send-dialog {
  background: var(--color-bg-white);
  border-radius: var(--radius-xl);
  padding: var(--space-xl) var(--space-2xl);
  min-width: 420px;
  max-width: 560px;
  box-shadow: var(--shadow-lg);
  text-align: center;
}

.email-send-dialog h3 {
  margin-bottom: var(--space-lg);
}

.email-send-stats {
  display: flex;
  justify-content: center;
  gap: var(--space-xl);
  font-size: var(--font-size-sm);
  margin-bottom: var(--space-sm);
}

.email-progress-log {
  max-height: 150px;
  overflow-y: auto;
  text-align: left;
  font-size: var(--font-size-xs);
  margin-top: var(--space-md);
}

.email-progress-log-item {
  padding: 2px 0;
}

.email-progress-log-item.error {
  color: var(--color-danger);
}

@media (max-width: 1024px) {
  .grid-email-compose {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .email-send-dialog {
    min-width: auto;
    margin: var(--space-md);
  }
}

/* --- Print (hide nav/footer) --- */
@media print {
  .navbar, .footer, .mobile-menu, .toast-container {
    display: none !important;
  }
  .main-content {
    padding-top: 0;
  }
}

/* ============================================
   向陳老師提問 — 學員端
   ============================================ */
.teacher-qa-section {
  margin-top: 1.5rem;
  background: var(--color-bg-navy);
  border: 1px solid rgba(212,165,116,.2);
  border-radius: 12px;
  overflow: hidden;
}
.teacher-qa-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: .75rem 1rem;
  background: rgba(212,165,116,.08);
  border-bottom: 1px solid rgba(212,165,116,.15);
}
.teacher-qa-title {
  font-weight: 700;
  color: var(--color-gold);
  font-size: 1rem;
}
.teacher-qa-subtitle {
  font-size: .8rem;
  color: var(--color-text-light);
}
.teacher-qa-form {
  padding: 1rem;
}
.teacher-qa-input {
  width: 100%;
  background: rgba(255,255,255,.06);
  border: 1px solid rgba(212,165,116,.2);
  border-radius: 8px;
  color: var(--color-text);
  padding: .6rem .8rem;
  font-size: .9rem;
  resize: vertical;
  min-height: 60px;
  font-family: inherit;
}
.teacher-qa-input:focus {
  outline: none;
  border-color: var(--color-gold);
}
.teacher-qa-input::placeholder {
  color: var(--color-text-light);
}
.teacher-qa-form-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: .5rem;
}
.teacher-qa-charcount {
  font-size: .75rem;
  color: var(--color-text-light);
}
.teacher-qa-submit {
  padding: .4rem 1.2rem;
  font-size: .85rem;
}

/* 歷史問答 */
.teacher-qa-history {
  padding: 0 1rem 1rem;
}
.teacher-qa-loading, .teacher-qa-empty {
  text-align: center;
  padding: 1.5rem 0;
  color: var(--color-text-light);
  font-size: .85rem;
}
.teacher-qa-list-title {
  font-size: .8rem;
  color: var(--color-text-light);
  margin-bottom: .75rem;
  padding-top: .5rem;
  border-top: 1px solid rgba(212,165,116,.1);
}
.teacher-qa-item {
  background: rgba(255,255,255,.03);
  border: 1px solid rgba(212,165,116,.12);
  border-radius: 8px;
  padding: .75rem;
  margin-bottom: .75rem;
}
.teacher-qa-item.answered {
  border-left: 3px solid #4caf50;
}
.teacher-qa-item.pending {
  border-left: 3px solid var(--color-gold);
}
.tqa-question-row {
  display: flex;
  align-items: center;
  gap: .5rem;
  flex-wrap: wrap;
  margin-bottom: .4rem;
}
.tqa-status-badge {
  font-size: .7rem;
  padding: .15rem .5rem;
  border-radius: 10px;
  font-weight: 600;
}
.tqa-status-badge.pending {
  background: rgba(212,165,116,.2);
  color: var(--color-gold);
}
.tqa-status-badge.answered {
  background: rgba(76,175,80,.2);
  color: #4caf50;
}
.tqa-lesson-tag {
  font-size: .7rem;
  background: rgba(255,255,255,.06);
  padding: .1rem .4rem;
  border-radius: 4px;
  color: var(--color-text-light);
}
.tqa-time {
  font-size: .7rem;
  color: var(--color-text-light);
  margin-left: auto;
}
.tqa-question-text {
  font-size: .88rem;
  color: var(--color-text);
  line-height: 1.5;
}
.tqa-answer {
  margin-top: .6rem;
  padding: .6rem .75rem;
  background: rgba(76,175,80,.06);
  border-radius: 6px;
  border-left: 3px solid #4caf50;
}
.tqa-answer-label {
  font-size: .75rem;
  color: #4caf50;
  font-weight: 600;
  margin-bottom: .3rem;
}
.tqa-answer-text {
  font-size: .88rem;
  color: var(--color-text);
  line-height: 1.5;
}

/* toast 提示 */
.teacher-qa-toast {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  background: #4caf50;
  color: #fff;
  padding: .6rem 1.5rem;
  border-radius: 8px;
  font-size: .9rem;
  z-index: 9999;
  animation: tqaToastFade 3s ease forwards;
}
@keyframes tqaToastFade {
  0%,70% { opacity: 1; }
  100% { opacity: 0; }
}

/* ============================================
   向陳老師提問 — 管理後台
   ============================================ */
.tqa-admin-list {
  display: flex;
  flex-direction: column;
  gap: .75rem;
}
.tqa-admin-card {
  background: #faf6f0;
  border: 1px solid rgba(180,150,110,.25);
  border-radius: 10px;
  padding: 1rem;
  color: #333;
}
.tqa-admin-card.pending {
  border-left: 4px solid var(--color-gold);
}
.tqa-admin-card.answered {
  border-left: 4px solid #4caf50;
}
.tqa-admin-meta {
  display: flex;
  align-items: center;
  gap: .5rem;
  flex-wrap: wrap;
  margin-bottom: .5rem;
  font-size: .85rem;
}
.tqa-admin-course {
  background: rgba(180,130,70,.12);
  padding: .1rem .4rem;
  border-radius: 4px;
  font-size: .75rem;
  color: #8b6914;
}
.tqa-admin-lesson {
  background: rgba(0,0,0,.06);
  padding: .1rem .4rem;
  border-radius: 4px;
  font-size: .75rem;
  color: #666;
}
.tqa-admin-question {
  font-size: .95rem;
  color: #222;
  line-height: 1.6;
  margin-bottom: .5rem;
}
.tqa-admin-answer {
  background: rgba(76,175,80,.08);
  border-left: 3px solid #4caf50;
  border-radius: 6px;
  padding: .6rem .75rem;
  margin-bottom: .5rem;
  color: #333;
}
.tqa-admin-actions {
  display: flex;
  gap: .5rem;
}
.tqa-reply-form {
  margin-top: .75rem;
  padding-top: .75rem;
  border-top: 1px solid rgba(0,0,0,.1);
}
.tqa-reply-form textarea {
  background: #fff;
  border: 1px solid #ccc;
  color: #222;
  border-radius: 8px;
  font-family: inherit;
  width: 100%;
  min-height: 160px;
  padding: 12px;
  font-size: 15px;
  line-height: 1.6;
  resize: vertical;
  box-sizing: border-box;
}
.tqa-reply-form textarea:focus {
  outline: none;
  border-color: var(--color-gold);
}

/* 手機適配 */
@media (max-width: 768px) {
  .teacher-qa-header {
    flex-direction: column;
    align-items: flex-start;
    gap: .2rem;
  }
  .tqa-admin-meta {
    font-size: .78rem;
  }
}