/* Lesson detail page (Pencil: LessonDetailPage) */

.lesson-breadcrumb {
  padding: 16px 0;
  background: var(--color-bg-primary);
}

.lesson-breadcrumb .breadcrumb-content {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-size: 14px;
}

.lesson-breadcrumb a {
  color: #64748B;
}

.lesson-breadcrumb .current {
  color: #2563EB;
  font-weight: 500;
}

.lesson-hero {
  padding: 40px 0;
  background: var(--color-bg-primary);
}

.lesson-title-section {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  gap: 20px;
  align-items: flex-start;
}

.lesson-icon {
  flex-shrink: 0;
}

.lesson-icon svg {
  width: 56px;
  height: 56px;
}

.lesson-badge {
  display: flex;
  align-items: center;
  gap: 8px;
}

.lesson-type-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 5px 10px;
  border-radius: 6px;
  background: #2563EB;
  color: #FFFFFF;
  font-size: 12px;
  font-weight: 600;
}

.lesson-info h1 {
  margin-top: 8px;
  font-size: 28px;
  font-weight: 800;
  line-height: 1.2;
  color: var(--color-text-primary);
}

.lesson-info > p {
  margin-top: 8px;
  font-size: 14px;
  font-weight: 400;
  line-height: 1.6;
  color: var(--color-text-secondary);
  max-width: 720px;
}

.lesson-meta-row {
  margin-top: 10px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  font-size: 12px;
  color: #64748B;
}

.lesson-meta-item {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 6px 10px;
  background: #F8FAFC;
  border: 1px solid #E2E8F0;
  border-radius: 12px;
}

.lesson-meta-item .k {
  color: #94A3B8;
}

.lesson-meta-item .v {
  color: #0F172A;
  font-weight: 500;
}

.lesson-progress {
  margin-top: 16px;
}

.progress-header {
  display: flex;
  justify-content: space-between;
  font-size: 14px;
  font-weight: 500;
  color: #64748B;
  margin-bottom: 8px;
}

.progress-bar {
  height: 8px;
  border-radius: 4px;
  background: #E2E8F0;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: #2563EB;
  border-radius: 4px;
  width: 0;
}

.lesson-content {
  padding: 0 0 80px;
  background: var(--color-bg-primary);
}

.lesson-main {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  gap: 32px;
}

.content-area {
  flex: 1;
  max-width: 840px;
}

.card {
  background: #FFFFFF;
  border-radius: 22px;
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-lg);
}

.lesson-page-card {
  padding: 32px 28px;
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.page-indicator {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
  font-size: 14px;
  color: #64748B;
}

.page-indicator-left {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-indicator-title {
  font-size: 15px;
  font-weight: 600;
  color: #0F172A;
}

.page-indicator-sub {
  font-size: 13px;
  color: #64748B;
}

.page-nav-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: flex-end;
}

.page-nav-item {
  border-radius: 999px;
  border: 1px solid #E2E8F0;
  padding: 6px 12px;
  background: #F8FAFC;
  color: #475569;
  font-size: 12px;
  cursor: pointer;
  white-space: nowrap;
}

.page-nav-item:hover {
  border-color: #2563EB;
  color: #1D4ED8;
  background: #EFF6FF;
}

.lesson-content-section {
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.lesson-page-block {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.lesson-page-heading {
  font-size: 18px;
  font-weight: 700;
  color: #0F172A;
}

.lesson-content-section p {
  font-size: 16px;
  font-weight: 400;
  line-height: 1.7;
  color: var(--color-text-primary);
}

.lesson-image {
  max-width: 180px;
  margin: 0 auto;
  padding: 8px 9px;
  border-radius: 18px;
  background: #F8FAFC;
  border: 1px solid #E2E8F0;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: zoom-in;
}

.lesson-image img {
  border-radius: 12px;
  display: block;
  max-width: 100%;
  max-height: 130px;
  width: auto;
  height: auto;
  object-fit: contain;
}

/* Theory migrated: audio demo card */
.lesson-audio-card {
  border: 1px solid #E2E8F0;
  border-radius: 16px;
  padding: 14px 14px;
  background: #FFFFFF;
}
.lesson-audio-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
.lesson-audio-row .btn-page-primary {
  padding: 8px 14px;
  border-radius: 999px;
  font-size: 13px;
}
.lesson-audio-title {
  font-size: 14px;
  font-weight: 700;
  color: #0F172A;
}
.lesson-audio-time {
  margin-top: 8px;
  font-size: 12px;
  color: #64748B;
}

.lesson-image .image-placeholder {
  width: 150px;
  height: 100px;
  border-radius: 16px;
  background: #F1F5F9;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #64748B;
}

.page-navigation {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding-top: 24px;
}

.page-navigation .btn {
  border-radius: 12px;
  padding: 14px 24px;
}

.btn-page-secondary {
  background: #F8FAFC;
  border: 1px solid #E2E8F0;
  color: #64748B;
  font-weight: 500;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.btn-page-primary {
  background: #2563EB;
  color: #FFFFFF;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.btn-page-secondary[disabled],
.btn-page-primary[disabled] {
  opacity: 0.6;
  pointer-events: none;
}

.sidebar {
  width: 320px;
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.sidebar-card {
  padding: 24px 22px;
  border-radius: 22px;
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-lg);
}

.sidebar-card h3 {
  font-size: 18px;
  font-weight: 700;
  color: #18181B;
  margin-bottom: 24px;
}

.chapter-item h4 {
  font-size: 16px;
  font-weight: 600;
  color: #18181B;
  margin-bottom: 16px;
}

.lessons {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.lesson-link {
  padding: 12px 0;
  font-size: 14px;
  color: #64748B;
}

.lesson-link.active {
  color: #2563EB;
  font-weight: 600;
}

.help-card {
  border-radius: 18px;
  padding: 24px 22px;
  background: #F0F9FF;
  border: 1px solid #BAE6FD;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.help-card h3 {
  font-size: 16px;
  font-weight: 700;
  color: #18181B;
}

.help-card p {
  font-size: 14px;
  font-weight: 400;
  line-height: 1.6;
  color: #475569;
}

/* Summary + Quiz section */
.lesson-summary-section {
  padding: 60px 0;
  background: var(--color-bg-primary);
}

.summary-stack {
  display: flex;
  flex-direction: column;
  gap: 32px;
  align-items: center;
}

.summary-card {
  width: 100%;
  max-width: 900px;
  border-radius: 22px;
  background: #FFFFFF;
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-lg);
  padding: 32px 32px;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

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

.summary-title-row .t {
  font-size: 20px;
  font-weight: 700;
  color: #18181B;
}

.summary-points {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.summary-points p {
  font-size: 15px;
  font-weight: 400;
  line-height: 1.6;
  color: #374151;
}

.quiz-card {
  width: 100%;
  max-width: 900px;
  border-radius: 22px;
  background: #F8FAFC;
  border: 1px solid var(--color-border);
  padding: 32px 32px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

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

.quiz-title-row .t {
  font-size: 20px;
  font-weight: 700;
  color: #18181B;
}

.quiz-desc {
  font-size: 14px;
  font-weight: 400;
  color: #64748B;
}

.quiz-start-btn {
  width: 200px;
  border-radius: 12px;
  background: #2563EB;
  color: #FFFFFF;
  padding: 14px 24px;
  font-size: 15px;
  font-weight: 600;
  text-align: center;
}

/* Related practice tools section */
.lesson-practice-tools {
  padding: 80px 0;
  background: #F8FAFC;
}

.practice-tools-header {
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 40px;
}

.practice-tools-header h2 {
  font-size: 26px;
  font-weight: 800;
  color: var(--color-text-primary);
}

.practice-tools-header p {
  font-size: 14px;
  font-weight: 400;
  color: var(--color-text-tertiary);
}

.practice-tools-grid {
  width: 1200px;
  margin: 0 auto;
  display: flex;
  gap: 24px;
  justify-content: center;
  flex-wrap: wrap;
}

.practice-tool-mini {
  width: 100%;
  border-radius: 22px;
  background: #FFFFFF;
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-lg);
  padding: 22px 20px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.sidebar-practice-card {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.sidebar-practice-card h3 {
  font-size: 16px;
  font-weight: 700;
  color: #18181B;
}

.sidebar-practice-subtitle {
  font-size: 12px;
  line-height: 1.6;
  color: var(--color-text-tertiary);
}

.sidebar-practice-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.practice-tool-mini .mini-icon {
  width: 64px;
  height: 64px;
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.practice-tool-mini .mini-title {
  font-size: 15px;
  font-weight: 700;
  color: #18181B;
}

.practice-tool-mini .mini-desc {
  font-size: 12px;
  line-height: 1.6;
  color: #64748B;
}

.practice-tool-mini .mini-stats {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 12px;
}

.practice-tool-mini .mini-stats .left {
  font-size: 12px;
  color: #94A3B8;
}

.mini-diff {
  border-radius: 4px;
  padding: 4px 8px;
  font-size: 11px;
  font-weight: 600;
}

.mini-btn {
  margin-top: 0;
  width: 100%;
  border-radius: 12px;
  padding: 12px 0;
  font-size: 14px;
  font-weight: 600;
  text-align: center;
  color: #FFFFFF;
}

@media (max-width: 1024px) {
  .lesson-title-section { padding: 0 20px; }
  .lesson-main { flex-direction: column; }
  .sidebar { width: 100%; }
  .content-area { max-width: 100%; }
  .summary-card, .quiz-card { width: 100%; }
  .practice-tools-grid { width: 100%; padding: 0 20px; }
}