/* Lessons page — clean 3-column layout */

/* Enhanced header nav */
.header--lessons .nav--enhanced {
  gap: 1.25rem;
}

.nav-links--enhanced {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  list-style: none;
}

.nav-group {
  display: flex;
  align-items: center;
  gap: 0.65rem;
}

.nav-group-label {
  font-size: 0.65rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  opacity: 0.75;
  white-space: nowrap;
}

.nav-group-links {
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.nav-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.45rem 0.75rem;
  border-radius: 999px;
  text-decoration: none;
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text-muted);
  background: transparent;
  border: 1.5px solid transparent;
  transition: color 0.2s, background 0.2s, border-color 0.2s;
}

.nav-pill:hover {
  color: var(--text);
  background: rgba(255, 255, 255, 0.6);
}

.nav-pill--active {
  color: var(--red);
  background: var(--red-light);
  border-color: rgba(199, 62, 58, 0.2);
}

.nav-pill--active .nav-icon {
  color: var(--red);
}

.nav-icon {
  flex-shrink: 0;
  color: var(--text-muted);
  transition: color 0.2s;
}

.nav-pill:hover .nav-icon {
  color: var(--text);
}

.nav-group--secondary .nav-group-links {
  gap: 0.15rem;
}

.nav-group--secondary .nav-group-links a {
  padding: 0.4rem 0.6rem;
  border-radius: 8px;
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-muted);
  transition: color 0.2s, background 0.2s;
}

.nav-group--secondary .nav-group-links a:hover {
  color: var(--text);
  background: rgba(255, 255, 255, 0.5);
}

.nav-actions--enhanced {
  align-items: center;
  gap: 0.6rem;
}

.nav-actions--enhanced .auth-nav-slot {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.btn-next-word {
  white-space: nowrap;
}

.lessons-page {
  min-height: calc(100vh - 72px);
}

.lessons-hero--compact {
  padding: 1.5rem 0 1rem;
}

.lessons-hero--compact h1 {
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 700;
  margin: 0 0 0.25rem;
}

.lessons-hero-sub {
  margin: 0 0 1rem;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.lessons-hero-progress {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  max-width: 420px;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-muted);
}

.lessons-hero-progress .progress-bar {
  flex: 1;
}

.lessons-hero-progress #progress-percent {
  color: var(--red);
  min-width: 2.5rem;
  text-align: right;
}

.lessons-learn {
  padding: 0 0 3rem;
}

.lessons-shell {
  display: grid;
  grid-template-columns: 240px minmax(0, 1fr);
  gap: 1.25rem;
  align-items: start;
}

/* Sidebar */
.lessons-sidebar {
  position: sticky;
  top: 88px;
  display: flex;
  flex-direction: column;
  gap: 1rem;
  max-height: calc(100vh - 110px);
}

.sidebar-block {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.85rem;
}

.sidebar-block--grow {
  flex: 1;
  min-height: 0;
  display: flex;
  flex-direction: column;
}

.sidebar-label {
  display: block;
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-bottom: 0.6rem;
}

.level-tabs {
  display: grid;
  gap: 0.35rem;
}

.level-tab {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 100%;
  padding: 0.55rem 0.7rem;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface);
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text);
  cursor: pointer;
  transition: border-color 0.2s, background 0.2s;
}

.level-tab-label {
  font-weight: 700;
}

.level-tab-sub {
  display: block;
  margin-top: 0.1rem;
  font-size: 0.68rem;
  font-weight: 600;
  color: var(--text-muted);
  line-height: 1.2;
}

.level-tab.active .level-tab-sub {
  color: var(--red);
  opacity: 0.85;
}

.level-tab:hover {
  border-color: var(--navy-light);
}

.level-tab.active {
  border-color: var(--red);
  background: var(--red-light);
  color: var(--red);
}

.level-tab.active .level-tab-label {
  color: var(--red);
}

.grade-tab.hidden {
  display: none;
}

.grade-tabs-block.hidden {
  display: none;
}

.grade-tabs {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.35rem;
}

.grade-tab {
  display: flex;
  justify-content: center;
  align-items: center;
  width: 100%;
  padding: 0.5rem 0.4rem;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface);
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--text);
  cursor: pointer;
  transition: border-color 0.2s, background 0.2s;
}

.grade-tab-label {
  font-weight: 700;
}

.grade-tab:hover {
  border-color: var(--navy-light);
}

.grade-tab.active {
  border-color: var(--navy);
  background: var(--navy-light);
  color: var(--navy);
}

.grade-tab.active .grade-tab-label {
  color: var(--navy);
}

.grade-tab--soon {
  opacity: 0.72;
}

.lesson-nav-part {
  padding: 0.45rem 0.35rem 0.2rem;
  font-size: 0.62rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
}

.lessons-coming-soon {
  padding: 2rem 1rem;
  text-align: center;
  color: var(--text-muted);
}

.lessons-coming-soon h3 {
  margin: 0 0 0.5rem;
  font-size: 1.05rem;
  color: var(--text);
}

.lesson-nav {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  overflow-y: auto;
  flex: 1;
  min-height: 0;
}

.lesson-nav-item {
  display: grid;
  grid-template-columns: 2rem 1fr auto;
  align-items: center;
  gap: 0.5rem;
  width: 100%;
  padding: 0.55rem 0.5rem;
  border: none;
  border-radius: var(--radius-sm);
  background: transparent;
  text-align: left;
  cursor: pointer;
  transition: background 0.15s;
}

.lesson-nav-item:hover {
  background: var(--cream);
}

.lesson-nav-item.selected {
  background: var(--red-light);
  border-left: 3px solid var(--red);
  padding-left: calc(0.5rem - 3px);
}

.lesson-nav-item.completed .lesson-nav-num {
  color: var(--red);
}

.lesson-nav-num {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--text-muted);
}

.lesson-nav-text {
  min-width: 0;
}

.lesson-nav-title {
  display: block;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--navy);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.lesson-nav-kr {
  display: block;
  font-size: 0.68rem;
  color: var(--text-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.lesson-nav-pct {
  font-size: 0.68rem;
  font-weight: 700;
  color: var(--text-muted);
}

.lesson-nav-item.selected .lesson-nav-pct {
  color: var(--red);
}

/* Workspace */
.lessons-workspace {
  min-width: 0;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.1rem;
}

.lesson-breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.35rem;
  margin-bottom: 0.85rem;
  padding: 0.55rem 0.75rem;
  background: var(--cream);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-muted);
  line-height: 1.4;
}

.lesson-breadcrumb-part {
  color: var(--navy);
}

.lesson-breadcrumb-part:last-of-type {
  color: var(--red);
}

.lesson-breadcrumb-sep {
  color: var(--text-muted);
  opacity: 0.55;
  user-select: none;
}

.lesson-header {
  margin-bottom: 1rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border);
}

.lesson-header-top {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1rem;
  margin-bottom: 0.65rem;
}

.lesson-header-num {
  margin: 0 0 0.15rem;
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--red);
}

.lesson-header-title {
  margin: 0 0 0.25rem;
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--navy);
  line-height: 1.3;
}

.lesson-header-desc {
  margin: 0;
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.45;
}

.lesson-curriculum-badge {
  display: inline-block;
  margin: 0.45rem 0 0;
  padding: 0.3rem 0.6rem;
  font-size: 0.72rem;
  font-weight: 600;
  line-height: 1.4;
  color: var(--navy);
  background: var(--navy-light);
  border-radius: 100px;
}

.lesson-header-meta {
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--text-muted);
  white-space: nowrap;
}

.lesson-header-meta #filter-category-percent {
  color: var(--red);
}

.lesson-header-meta-sep {
  opacity: 0.5;
}

.lesson-header-bar {
  height: 5px;
  margin-bottom: 0.65rem;
}

.lesson-guide-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.35rem 0.6rem;
  border: none;
  background: var(--cream);
  border-radius: var(--radius-sm);
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-muted);
  cursor: pointer;
}

.lesson-guide-toggle[aria-expanded="true"] svg {
  transform: rotate(180deg);
}

.lesson-guide {
  margin-top: 0.75rem;
  padding: 0.85rem;
  background: var(--cream);
  border-radius: var(--radius-sm);
  font-size: 0.84rem;
  line-height: 1.55;
  color: var(--text);
}

.lesson-guide.hidden {
  display: none;
}

.lesson-guide-curriculum {
  margin: 0 0 0.65rem;
  padding: 0.45rem 0.6rem;
  background: var(--navy-light);
  border-radius: 6px;
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--navy);
  line-height: 1.45;
}

.lesson-guide-block {
  margin-bottom: 0.65rem;
}

.lesson-guide-goals {
  margin: 0.2rem 0 0;
  padding-left: 1.15rem;
  font-size: 0.8rem;
  line-height: 1.5;
}

.lesson-guide-goals li {
  margin-bottom: 0.2rem;
}

.lesson-guide-grammar,
.lesson-guide-culture {
  margin: 0 0 0.5rem;
  font-size: 0.8rem;
  line-height: 1.5;
  color: var(--text);
}

.lesson-guide-grammar {
  font-weight: 600;
  color: var(--navy);
}

.lesson-guide-culture {
  padding: 0.55rem 0.65rem;
  background: var(--surface);
  border-radius: 6px;
  border: 1px solid var(--border);
  color: var(--text-muted);
}

.lesson-guide-theme {
  margin: 0 0 0.35rem;
  font-weight: 700;
  color: var(--red);
}

.lesson-guide-hook {
  margin: 0 0 0.5rem;
  font-weight: 600;
  color: var(--navy);
}

.lesson-guide-mission {
  margin: 0.5rem 0 0;
  padding-top: 0.5rem;
  border-top: 1px dashed var(--border);
  font-weight: 600;
  color: var(--red);
}

.lesson-guide-tip {
  margin: 0.35rem 0 0;
  color: var(--text-muted);
  font-size: 0.8rem;
}

/* Unit tabs */
.unit-tabs {
  display: flex;
  gap: 0.35rem;
  margin-bottom: 1rem;
  padding: 0.25rem;
  background: var(--cream);
  border-radius: var(--radius-sm);
}

.unit-tab {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.2rem;
  padding: 0.5rem 0.65rem;
  border: none;
  border-radius: 6px;
  background: transparent;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-muted);
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}

.unit-tab-label {
  font-weight: 700;
}

.unit-tab-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 2.4rem;
  padding: 0.1rem 0.4rem;
  border-radius: 999px;
  background: rgba(0, 0, 0, 0.05);
  font-size: 0.68rem;
  font-weight: 700;
  color: var(--text-muted);
  line-height: 1.3;
}

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

.unit-tab.active {
  background: var(--surface);
  color: var(--navy);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
}

.unit-tab.active .unit-tab-badge {
  background: var(--navy-light);
  color: var(--navy);
}

.unit-tab--complete .unit-tab-badge {
  background: rgba(46, 125, 78, 0.12);
  color: #2e7d4e;
}

.unit-tab--complete .unit-tab-badge::before {
  content: '✓ ';
}

/* Study panel */
.study-panel {
  min-height: 100px;
}

.word-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
}

/* .hidden must beat .word-grid — lessons.css loads after hangul.css */
.word-grid.hidden {
  display: none;
}

.study-card,
.word-card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  background: var(--surface);
  border: 1.5px solid var(--border);
  border-radius: var(--radius);
  padding: 1.15rem 1.1rem;
  text-align: left;
  cursor: pointer;
  transition: border-color 0.15s, box-shadow 0.15s;
  min-height: 100%;
}

.study-card:hover,
.word-card:hover {
  border-color: var(--navy-light);
  box-shadow: var(--shadow);
}

.study-card.selected,
.word-card.selected {
  border-color: var(--red);
  box-shadow: 0 0 0 2px var(--red-glow);
}

.study-card.learned,
.word-card.learned {
  background: linear-gradient(180deg, var(--surface) 0%, rgba(199, 62, 58, 0.04) 100%);
}

.study-card-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 0.75rem;
}

.study-card-headline {
  flex: 1;
  min-width: 0;
}

.study-card-play {
  flex-shrink: 0;
  width: 36px;
  height: 36px;
  border: 1.5px solid var(--border);
  border-radius: 50%;
  background: var(--surface);
  color: var(--red);
  cursor: pointer;
  display: grid;
  place-items: center;
  transition: border-color 0.2s, background 0.2s;
}

.study-card-play:hover {
  border-color: var(--red);
  background: var(--red-light);
}

.study-card-play--sm {
  width: 30px;
  height: 30px;
}

.study-card-example {
  padding: 0.75rem 0.85rem;
  background: var(--cream);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
}

.study-card-example-label {
  display: block;
  margin-bottom: 0.35rem;
  font-size: 0.62rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
}

.study-card-example-kr {
  margin: 0 0 0.4rem;
  font-size: 0.95rem;
  line-height: 1.5;
  color: var(--navy);
  word-break: keep-all;
}

.study-card-example-foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
}

.study-card-example-en {
  margin: 0;
  flex: 1;
  font-size: 0.8rem;
  line-height: 1.45;
  color: var(--text-muted);
}

.study-card-tip {
  padding: 0.65rem 0.75rem;
  background: var(--cream);
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  line-height: 1.45;
  color: var(--text-muted);
}

.study-card-tip p {
  margin: 0.2rem 0 0;
}

.study-card-tip-label {
  font-size: 0.62rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
}

.study-card-footer {
  display: flex;
  align-items: center;
  margin-top: auto;
  padding-top: 0.15rem;
}

.study-card-learned {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.45rem 0.75rem;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--cream);
  color: var(--text-muted);
  font-family: var(--font-ui);
  font-size: 0.78rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s, color 0.2s;
}

.study-card-learned:hover {
  border-color: var(--red);
  color: var(--red);
}

.study-card-learned.is-learned {
  background: var(--red-light);
  border-color: var(--red);
  color: var(--red);
}

.word-card-kr {
  font-size: clamp(1.25rem, 2.2vw, 1.55rem);
  line-height: 1.35;
  margin-bottom: 0.2rem;
  color: var(--navy);
  white-space: normal;
  word-break: keep-all;
  overflow-wrap: anywhere;
}

.word-card-kr--multi {
  font-size: 1.05rem;
}

.word-card--sentence .word-card-kr {
  font-size: 1rem;
  line-height: 1.45;
}

.word-card-roman {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-bottom: 0.35rem;
}

.word-card-meaning {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--red);
}

.word-card-source {
  margin-top: 0.45rem;
  font-size: 0.68rem;
  font-weight: 700;
  color: var(--red);
  line-height: 1.3;
}

.lessons-empty {
  grid-column: 1 / -1;
  margin: 0;
  padding: 2rem 1rem;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* Culture / PPT Lecture */
.culture-panel.hidden {
  display: none;
}

.lecture-card {
  padding: 0.25rem 0;
}

.lecture-title {
  margin: 0 0 0.2rem;
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--navy);
}

.lecture-subtitle {
  margin: 0 0 0.35rem;
  font-size: 0.95rem;
  color: var(--text-muted);
}

.lecture-grammar {
  margin: 0 0 0.5rem;
  font-size: 0.82rem;
  color: var(--navy);
}

.lecture-guide {
  margin: 0 0 0.85rem;
  font-size: 0.88rem;
  line-height: 1.5;
  color: var(--text);
}

.lecture-sections {
  margin: 0 0 0.85rem;
}

.lecture-sections ul {
  margin: 0.35rem 0 0;
  padding-left: 1.1rem;
  font-size: 0.82rem;
  color: var(--text-muted);
  line-height: 1.45;
}

.lecture-card-header {
  margin-bottom: 0.75rem;
}

.lecture-viewer-wrap {
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  overflow: hidden;
  background: #f0eeea;
}

.lecture-slide-viewer {
  display: flex;
  flex-direction: column;
}

.lecture-slide-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  flex-wrap: wrap;
  padding: 0.55rem 0.75rem;
  background: var(--surface);
  border-bottom: 1.5px solid var(--border);
}

.lecture-slide-expand {
  margin-left: auto;
  padding: 0.4rem 0.75rem;
  font-size: 0.78rem;
  font-weight: 700;
  color: #fff;
  background: var(--red);
  border: 0;
  border-radius: var(--radius-sm);
  cursor: pointer;
}

.lecture-slide-expand:hover {
  opacity: 0.92;
}

.lecture-slide-img-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  padding: 0;
  border: 0;
  background: transparent;
  cursor: zoom-in;
}

.lecture-slide-nav {
  display: inline-flex;
  align-items: center;
  gap: 0.2rem;
  padding: 0.4rem 0.75rem;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--navy);
  background: var(--cream, #f7f5f0);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
}

.lecture-slide-nav:hover:not(:disabled) {
  border-color: var(--red);
  color: var(--red);
}

.lecture-slide-nav:disabled {
  opacity: 0.35;
  cursor: not-allowed;
}

.lecture-slide-count {
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--navy);
  min-width: 4.5rem;
  text-align: center;
}

.lecture-slide-stage {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: min(68vh, 520px);
  padding: 0.75rem;
  background: #e8e6e2;
  overflow: hidden;
}

.lecture-slide-frame {
  display: block;
  width: 100%;
  height: min(68vh, 560px);
  border: 0;
  background: #fff;
  border-radius: 4px;
  box-shadow: 0 4px 24px rgba(26, 35, 50, 0.12);
  transition: opacity 0.25s ease, transform 0.25s ease;
}

.lecture-slide-frame--from-right {
  opacity: 0.35;
  transform: translateX(18px);
}

.lecture-slide-frame--from-left {
  opacity: 0.35;
  transform: translateX(-18px);
}

.lecture-slide-frame--settled {
  opacity: 1;
  transform: translateX(0);
}

.lecture-slide-img {
  display: block;
  max-width: 100%;
  max-height: min(68vh, 560px);
  width: auto;
  height: auto;
  margin: 0 auto;
  background: #fff;
  border-radius: 4px;
  box-shadow: 0 4px 24px rgba(26, 35, 50, 0.12);
  transition: opacity 0.25s ease, transform 0.25s ease;
}

.lecture-slide-img--from-right {
  opacity: 0.35;
  transform: translateX(18px);
}

.lecture-slide-img--from-left {
  opacity: 0.35;
  transform: translateX(-18px);
}

.lecture-slide-img--settled {
  opacity: 1;
  transform: translateX(0);
}

.lecture-slide-hint {
  margin: 0;
  padding: 0.5rem 0.75rem 0.65rem;
  font-size: 0.72rem;
  color: var(--text-muted);
  text-align: center;
  background: var(--surface);
  border-top: 1px solid var(--border);
}

/* PPT lightbox */
body.lecture-lightbox-open {
  overflow: hidden;
}

.lecture-lightbox {
  position: fixed;
  inset: 0;
  z-index: 9999;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
}

.lecture-lightbox.hidden {
  display: none;
}

.lecture-lightbox-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(15, 22, 35, 0.82);
}

.lecture-lightbox-panel {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  width: min(96vw, 1100px);
  max-height: 96vh;
  background: #fff;
  border-radius: var(--radius-sm);
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.35);
  overflow: hidden;
}

.lecture-lightbox-close {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  z-index: 2;
  width: 2rem;
  height: 2rem;
  font-size: 1rem;
  line-height: 1;
  color: var(--navy);
  background: rgba(255, 255, 255, 0.9);
  border: 1.5px solid var(--border);
  border-radius: 50%;
  cursor: pointer;
}

.lecture-lightbox-close:hover {
  border-color: var(--red);
  color: var(--red);
}

.lecture-lightbox-toolbar {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  padding: 0.65rem 2.5rem 0.55rem;
  background: var(--surface);
  border-bottom: 1.5px solid var(--border);
}

.lecture-lightbox-stage {
  display: flex;
  align-items: center;
  justify-content: center;
  flex: 1;
  min-height: 0;
  padding: 0.75rem;
  background: #e8e6e2;
  overflow: auto;
}

.lecture-lightbox-zoom-controls {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  margin-left: 0.5rem;
}

.lecture-zoom-btn,
.lecture-zoom-reset {
  min-width: 2.25rem;
  min-height: 2.25rem;
  padding: 0.25rem 0.5rem;
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--navy);
  background: var(--cream, #f7f5f0);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
}

.lecture-zoom-reset {
  font-size: 0.72rem;
  min-width: auto;
  padding: 0.35rem 0.55rem;
}

.lecture-zoom-btn:hover,
.lecture-zoom-reset:hover {
  border-color: var(--red);
  color: var(--red);
}

.lecture-zoom-label {
  min-width: 3rem;
  font-size: 0.75rem;
  font-weight: 700;
  text-align: center;
  color: var(--navy);
}

.lecture-lightbox-zoom-viewport {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100%;
  min-height: min(70vh, 560px);
  overflow: hidden;
  touch-action: none;
}

.lecture-lightbox-zoom-inner {
  transform-origin: center center;
  will-change: transform;
}

.lecture-lightbox-zoom-inner--animated {
  transition: transform 0.12s ease-out;
}

.lecture-lightbox-img {
  display: block;
  max-width: min(96vw, 1100px);
  max-height: calc(96vh - 140px);
  width: auto;
  height: auto;
  object-fit: contain;
  border-radius: 4px;
  box-shadow: 0 8px 32px rgba(26, 35, 50, 0.18);
  user-select: none;
  -webkit-user-drag: none;
}

/* Admin PPT upload */
.lecture-admin-panel {
  margin-bottom: 0.85rem;
  padding: 0.75rem 0.9rem;
  background: #fff8e8;
  border: 1.5px solid #e8c96a;
  border-radius: var(--radius-sm);
}

.lecture-admin-summary {
  font-size: 0.85rem;
  font-weight: 700;
  color: #8a5a00;
  cursor: pointer;
}

.lecture-admin-body {
  margin-top: 0.65rem;
}

.lecture-admin-hint,
.lecture-admin-note {
  margin: 0 0 0.55rem;
  font-size: 0.78rem;
  color: var(--text-muted);
  line-height: 1.45;
}

.lecture-admin-file-label {
  display: inline-block;
  margin-bottom: 0.35rem;
}

.lecture-admin-file-input {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  overflow: hidden;
}

.lecture-admin-file-btn {
  display: inline-block;
  padding: 0.45rem 0.85rem;
  font-size: 0.8rem;
  font-weight: 700;
  color: #fff;
  background: #8a5a00;
  border-radius: var(--radius-sm);
  cursor: pointer;
}

.lecture-admin-filename {
  margin: 0 0 0.55rem;
  font-size: 0.75rem;
  color: var(--navy);
  word-break: break-all;
}

.lecture-admin-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-bottom: 0.45rem;
}

.lecture-admin-save,
.lecture-admin-clear {
  min-height: 2.5rem;
  padding: 0.45rem 0.85rem;
  font-size: 0.8rem;
  font-weight: 700;
  border-radius: var(--radius-sm);
  border: 1.5px solid var(--border);
  cursor: pointer;
}

.lecture-admin-save {
  color: #fff;
  background: var(--red);
  border-color: var(--red);
}

.lecture-admin-save:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.lecture-admin-clear {
  color: var(--navy);
  background: var(--surface);
}

.lecture-admin-status {
  margin: 0;
  font-size: 0.78rem;
  color: #2d6a2d;
}

.lecture-admin-status--error {
  color: var(--red);
}

@media (max-width: 640px) {
  .lecture-slide-toolbar,
  .lecture-lightbox-toolbar {
    gap: 0.4rem;
    padding: 0.6rem 0.55rem;
  }

  .lecture-slide-nav,
  .lecture-slide-expand,
  .lecture-lightbox-close,
  .lecture-zoom-btn,
  .lecture-zoom-reset {
    min-height: 44px;
    min-width: 44px;
    padding: 0.5rem 0.75rem;
    font-size: 0.85rem;
  }

  .lecture-slide-expand {
    width: 100%;
    margin-left: 0;
    order: 4;
  }

  .lecture-slide-stage {
    min-height: 42vh;
    padding: 0.5rem;
  }

  .lecture-slide-img {
    max-height: 42vh;
  }

  .lecture-lightbox {
    padding: 0.35rem;
  }

  .lecture-lightbox-panel {
    width: 100%;
    max-height: 100vh;
    border-radius: 0.5rem;
  }

  .lecture-lightbox-toolbar {
    flex-wrap: wrap;
    padding: 0.55rem 2.75rem 0.5rem 0.5rem;
  }

  .lecture-lightbox-zoom-controls {
    width: 100%;
    justify-content: center;
    margin-left: 0;
    order: 3;
  }

  .lecture-lightbox-zoom-viewport {
    min-height: 55vh;
  }

  .lecture-lightbox-img {
    max-height: calc(100vh - 160px);
  }

  .lecture-lightbox-close {
    top: 0.35rem;
    right: 0.35rem;
  }

  .lecture-admin-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .lecture-admin-save,
  .lecture-admin-clear,
  .lecture-admin-file-btn {
    width: 100%;
    min-height: 44px;
  }
}

.culture-card {
  padding: 0.25rem 0;
}

.culture-type-badge {
  display: inline-block;
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--red);
  margin-bottom: 0.5rem;
}

.culture-source {
  margin: 0 0 0.15rem;
  font-size: 1rem;
  font-weight: 700;
  color: var(--navy);
}

.culture-source-kr {
  margin: 0 0 0.5rem;
  font-size: 0.82rem;
  color: var(--text-muted);
}

.culture-drama-link {
  display: inline-block;
  margin: 0 0 1rem;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--red);
  text-decoration: none;
}

.culture-drama-link:hover {
  text-decoration: underline;
}

.culture-youtube {
  display: flex;
  align-items: stretch;
  gap: 0.85rem;
  margin: 0 0 1rem;
  padding: 0.65rem;
  background: var(--surface);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  text-decoration: none;
  color: inherit;
  transition: border-color 0.15s, box-shadow 0.15s;
}

.culture-youtube:hover {
  border-color: #cc0000;
  box-shadow: var(--shadow);
}

.culture-youtube-thumb-wrap {
  position: relative;
  width: 120px;
  min-width: 120px;
  aspect-ratio: 16 / 9;
  flex-shrink: 0;
}

.culture-youtube-thumb {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 6px;
  background: var(--cream);
}

.culture-youtube-time {
  position: absolute;
  right: 0.35rem;
  bottom: 0.35rem;
  padding: 0.15rem 0.4rem;
  font-size: 0.68rem;
  font-weight: 800;
  font-variant-numeric: tabular-nums;
  color: #fff;
  background: rgba(0, 0, 0, 0.82);
  border-radius: 4px;
  letter-spacing: 0.02em;
}

.culture-youtube-text {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 0.2rem;
  min-width: 0;
}

.culture-youtube-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.1rem;
  height: 1.1rem;
  margin-right: 0.25rem;
  font-size: 0.55rem;
  color: #fff;
  background: #cc0000;
  border-radius: 4px;
  vertical-align: middle;
}

.culture-youtube-label {
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--navy);
  line-height: 1.35;
}

.culture-youtube-hint {
  font-size: 0.68rem;
  color: var(--text-muted);
  line-height: 1.4;
}

.culture-youtube-hint strong {
  font-weight: 800;
  color: var(--navy);
  font-variant-numeric: tabular-nums;
}

.culture-line-time {
  display: inline-flex;
  align-items: center;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.35rem 0.5rem;
  margin: 0 auto 0.65rem;
  padding: 0.4rem 0.65rem;
  background: #fff5f5;
  border: 1.5px solid rgba(204, 0, 0, 0.2);
  border-radius: 999px;
  font-size: 0.74rem;
  font-weight: 600;
  color: var(--navy);
  text-decoration: none;
  transition: border-color 0.15s, background 0.15s;
}

.culture-line-time:hover {
  background: #ffe8e8;
  border-color: var(--red);
}

.culture-line-time-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.15rem;
  height: 1.15rem;
  font-size: 0.5rem;
  color: #fff;
  background: #cc0000;
  border-radius: 50%;
}

.culture-line-time-text strong,
.culture-line-time-kr strong {
  font-weight: 800;
  font-variant-numeric: tabular-nums;
  color: var(--red);
}

.culture-line-time-kr {
  color: var(--text-muted);
}

.culture-line-time-kr::before {
  content: '·';
  margin-right: 0.35rem;
  color: var(--border);
}

.culture-line {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  margin-bottom: 0.25rem;
}

.culture-line-kr {
  margin: 0;
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--navy);
}

.culture-line-roman {
  margin: 0 0 0.2rem;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-muted);
  font-style: italic;
}

.culture-line-en {
  margin: 0 0 1rem;
  text-align: center;
  font-size: 0.9rem;
}

.culture-note {
  padding: 0.75rem;
  background: var(--cream);
  border-radius: var(--radius-sm);
  font-size: 0.84rem;
  line-height: 1.5;
  margin-bottom: 0.65rem;
}

.culture-note p {
  margin: 0.25rem 0 0;
}

.culture-clip-hint {
  margin: 0.75rem 0 0;
  font-size: 0.78rem;
  line-height: 1.45;
  color: var(--text-muted);
}

.culture-mission {
  margin: 0.5rem 0 0;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--red);
}

.lesson-content-label {
  display: block;
  font-size: 0.65rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  margin-bottom: 0.2rem;
}

/* Detail panel */
.detail-panel--hidden {
  display: none;
}

.word-level {
  display: inline-block;
  font-size: 0.65rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--navy);
  background: var(--navy-light);
  padding: 0.25rem 0.55rem;
  border-radius: 100px;
  margin-bottom: 0.85rem;
}

.detail-roman {
  text-align: center;
  font-size: 0.95rem;
  color: var(--text-muted);
  font-style: italic;
  margin-bottom: 0.25rem;
}

.detail-char {
  word-break: keep-all;
  line-height: 1.25;
}

/* hangul.css의 고정 font-size(4rem)가 Lessons 디테일에서도 적용되는 문제를 방지 */
.lessons-page .detail-char {
  font-size: clamp(1.8rem, 5.2vw, 2.6rem);
  text-align: center;
  white-space: normal;
  overflow-wrap: anywhere;
}

@media (max-width: 480px) {
  .lessons-page .detail-char {
    font-size: clamp(1.5rem, 7vw, 2.2rem);
  }
}

.detail-meaning {
  text-align: center;
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--red);
  margin-bottom: 1rem;
}

.detail-source {
  margin-bottom: 1rem;
  padding: 0.75rem;
  background: var(--cream);
  border-radius: var(--radius-sm);
  text-align: center;
}

.detail-source-type {
  display: inline-block;
  margin-left: 0.35rem;
  font-size: 0.65rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--red);
}

.detail-source-title {
  margin: 0.35rem 0 0.1rem;
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--navy);
}

.detail-source-kr {
  margin: 0 0 0.35rem;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.detail-source-scene {
  margin: 0;
  font-size: 0.78rem;
  line-height: 1.45;
  color: var(--text);
}

.detail-source-guide {
  display: inline-block;
  margin-top: 0.55rem;
  font-size: 0.76rem;
  font-weight: 700;
  color: var(--red);
  text-decoration: none;
}

.detail-source-guide:hover {
  text-decoration: underline;
}

.detail-meta {
  display: flex;
  justify-content: center;
  margin-bottom: 1rem;
}

.detail-example {
  background: var(--cream);
  border-radius: var(--radius-sm);
  padding: 0.85rem;
}

.example-sentence-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  margin-bottom: 0.25rem;
}

.example-kr {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--navy);
  line-height: 1.4;
  word-break: keep-all;
}

.example-play-btn {
  flex-shrink: 0;
  width: 30px;
  height: 30px;
  border: 1.5px solid var(--border);
  border-radius: 50%;
  background: var(--surface);
  color: var(--red);
  cursor: pointer;
  display: grid;
  place-items: center;
  transition: border-color 0.2s, background 0.2s;
}

.example-play-btn:hover {
  border-color: var(--red);
  background: var(--red-light);
}

.example-en {
  font-size: 0.85rem;
  color: var(--text-muted);
  text-align: center;
  line-height: 1.45;
}

.footer-links-inline {
  display: flex;
  gap: 1.25rem;
}

@media (min-width: 901px) and (max-width: 1100px) {
  .nav-group-label {
    display: none;
  }

  .nav-links--enhanced {
    gap: 0.75rem;
  }

  .lessons-shell {
    grid-template-columns: 200px minmax(0, 1fr);
  }
}

@media (max-width: 900px) {
  .lessons-sidebar {
    position: static;
    max-height: none;
  }

  .lessons-shell {
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  .sidebar-block--grow {
    max-height: 220px;
  }

  .lesson-nav {
    flex-direction: row;
    flex-wrap: nowrap;
    overflow-x: auto;
    overflow-y: hidden;
    gap: 0.35rem;
    padding-bottom: 0.25rem;
  }

  .lesson-nav-item {
    flex: 0 0 auto;
    min-width: 140px;
    grid-template-columns: 1.75rem 1fr;
  }

  .lesson-nav-pct {
    display: none;
  }

}

@media (max-width: 720px) {
  .lessons-hero--compact {
    padding: 1.25rem 0 0.85rem;
  }

  .lessons-hero-progress {
    flex-wrap: wrap;
    max-width: none;
    gap: 0.5rem;
  }

  .lessons-hero-progress .progress-bar {
    order: 3;
    flex: 1 1 100%;
  }

  .lessons-workspace {
    padding: 0.85rem;
  }

  .lesson-header-top {
    flex-direction: column;
    align-items: stretch;
    gap: 0.5rem;
  }

  .lesson-header-meta {
    white-space: normal;
  }

  .lesson-header-title {
    font-size: 1.15rem;
  }

  .unit-tabs {
    flex-wrap: nowrap;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
    gap: 0.25rem;
    padding: 0.35rem;
  }

  .unit-tabs::-webkit-scrollbar {
    display: none;
  }

  .unit-tab {
    flex: 0 0 auto;
    min-height: 44px;
    padding: 0.55rem 0.85rem;
    white-space: nowrap;
  }

  .level-tab,
  .grade-tab,
  .lesson-nav-item {
    min-height: 44px;
  }

  .word-card {
    padding: 0.9rem 0.75rem;
    min-height: 44px;
  }

  .culture-youtube {
    flex-direction: column;
  }

  .culture-youtube-thumb-wrap {
    width: 100%;
    min-width: 0;
    aspect-ratio: 16 / 9;
  }

  .example-play-btn {
    width: 44px;
    height: 44px;
  }

  .lesson-guide-toggle {
    min-height: 44px;
    padding: 0.5rem 0.75rem;
  }
}

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

  .sidebar-block--grow {
    max-height: 180px;
  }

  .lesson-nav-item {
    min-width: 120px;
  }
}