/**
 * RhyRhy English - Navigation & App Shell Styles
 */
.main-nav {
  position: sticky;
  top: 0;
  z-index: 1000;
  width: 100%;
  background: rgba(15, 23, 42, 0.94);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--surface-border);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.35);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  height: var(--nav-height);
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 12px;
  width: 100%;
  box-sizing: border-box;
}

/* Brand */
.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: #FFFFFF;
  text-decoration: none;
  flex-shrink: 0;
}

.brand-logo {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: 0 2px 12px var(--primary-glow);
  flex-shrink: 0;
  transition: transform 0.2s ease;
}

.brand-logo:hover {
  transform: scale(1.05);
}

.brand-logo svg {
  width: 100%;
  height: 100%;
  display: block;
}

.brand-text-wrap {
  display: inline-flex;
  align-items: center;
  gap: 7px;
}

.brand-name {
  font-size: 1.15rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: #F8FAFC;
  white-space: nowrap;
}

.brand-name strong {
  color: var(--primary-light);
  font-weight: 800;
}

.nav-beta-tag {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 2px 7px;
  font-size: 0.65rem;
  font-weight: 800;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  border-radius: var(--radius-full);
  background: linear-gradient(135deg, rgba(236, 72, 153, 0.2), rgba(99, 102, 241, 0.25));
  border: 1px solid rgba(236, 72, 153, 0.45);
  color: #F472B6;
  line-height: 1.2;
  box-shadow: 0 0 10px rgba(236, 72, 153, 0.25);
  user-select: none;
  white-space: nowrap;
}

/* Lesson Switcher Dropdown */
.nav-lesson-dropdown {
  position: relative;
}

.btn-lesson-menu {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  height: 38px;
  padding: 6px 14px;
  background-color: var(--surface-color);
  border: 1.5px solid var(--surface-border);
  border-radius: var(--radius-full);
  color: var(--text-main);
  font-size: 0.88rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
  white-space: nowrap;
  flex-shrink: 0;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.2);
}

.btn-lesson-menu:hover {
  background-color: var(--surface-color-alt);
  border-color: var(--primary-light);
  transform: translateY(-1px);
}

.lesson-btn-icon {
  font-size: 1.15rem;
  line-height: 1;
  display: flex;
  align-items: center;
  justify-content: center;
}

.lesson-menu-label {
  font-weight: 600;
  color: #FFFFFF;
  letter-spacing: -0.01em;
}

.dropdown-chevron {
  flex-shrink: 0;
  transition: transform 0.2s ease;
  color: var(--text-muted);
}

.nav-lesson-dropdown:hover .dropdown-chevron,
.btn-lesson-menu[aria-expanded="true"] .dropdown-chevron {
  transform: rotate(180deg);
  color: var(--primary-light);
}

.lesson-menu-dropdown {
  position: absolute;
  top: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%) translateY(-8px);
  width: 320px;
  max-width: calc(100vw - 24px);
  background-color: var(--surface-color);
  border: 1px solid var(--surface-border-hover);
  border-radius: var(--radius-lg);
  padding: 8px;
  box-shadow: 0 20px 45px rgba(0, 0, 0, 0.65), 0 0 24px var(--primary-glow);
  opacity: 0;
  visibility: hidden;
  transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
  z-index: 120;
}

.lesson-menu-dropdown.open {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) translateY(0);
}

.lesson-dropdown-header {
  padding: 8px 12px;
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--text-subtle);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  border-bottom: 1px solid var(--surface-border);
  margin-bottom: 6px;
}

.lesson-dropdown-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 10px 12px;
  border-radius: var(--radius-md);
  color: var(--text-main);
  text-decoration: none;
  transition: background-color 0.15s ease;
  margin-bottom: 4px;
}

.lesson-dropdown-item:last-child {
  margin-bottom: 0;
}

.lesson-dropdown-item:hover {
  background-color: var(--surface-color-alt);
}

.lesson-dropdown-item.active {
  background: var(--primary-glow);
  border: 1px solid rgba(99, 102, 241, 0.3);
}

.dropdown-item-left {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}

.dropdown-item-icon {
  font-size: 1.35rem;
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  background-color: var(--bg-color);
  border: 1px solid var(--surface-border);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.dropdown-item-text {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.dropdown-item-title-row {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.88rem;
  line-height: 1.3;
}

.dropdown-item-title-row strong {
  color: #FFFFFF;
}

.dropdown-item-topic {
  font-size: 0.76rem;
  color: var(--primary-light);
  font-weight: 600;
}

.dropdown-item-subtitle {
  font-size: 0.74rem;
  color: var(--text-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 165px;
}

.dropdown-item-status {
  flex-shrink: 0;
}

.status-done {
  font-size: 0.75rem;
  color: var(--accent-emerald);
  font-weight: 700;
  background: var(--accent-emerald-glow);
  padding: 2px 8px;
  border-radius: var(--radius-full);
}

.status-prog {
  font-size: 0.75rem;
  color: var(--text-muted);
  background-color: var(--bg-color);
  padding: 2px 8px;
  border-radius: var(--radius-full);
}

/* Right Actions */
.nav-right-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.btn-nav-action {
  position: relative;
  display: flex;
  align-items: center;
  gap: 6px;
  height: 40px;
  padding: 6px 14px;
  background: transparent;
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  color: var(--text-muted);
  font-size: 0.85rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.2s ease;
  user-select: none;
  flex-shrink: 0;
}

.btn-nav-action:hover:not(.disabled) {
  background-color: var(--surface-color);
  color: #FFFFFF;
}

.btn-nav-action.active {
  background: rgba(99, 102, 241, 0.16);
  border-color: rgba(99, 102, 241, 0.4);
  color: #FFFFFF;
}

.btn-nav-action.disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.nav-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 20px;
  height: 20px;
  padding: 0 6px;
  background-color: var(--primary);
  color: #FFFFFF;
  border-radius: var(--radius-full);
  font-size: 0.72rem;
  font-weight: 700;
}

.history-unlocked-dot {
  width: 7px;
  height: 7px;
  border-radius: var(--radius-full);
  background-color: var(--accent-emerald);
  position: absolute;
  top: 8px;
  right: 6px;
}

/* Offline Banner */
.offline-banner {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 8px 16px;
  background-color: #92400E;
  color: #FEF3C7;
  font-size: 0.82rem;
  font-weight: 500;
  text-align: center;
}

/* Drawers */
.app-drawer {
  position: fixed;
  inset: 0;
  z-index: 200;
  visibility: hidden;
  transition: visibility 0.3s;
}

.app-drawer.open {
  visibility: visible;
}

.drawer-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.65);
  backdrop-filter: blur(4px);
  opacity: 0;
  transition: opacity 0.3s ease;
}

.app-drawer.open .drawer-backdrop {
  opacity: 1;
}

.drawer-panel {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  width: 100%;
  max-width: 420px;
  background-color: var(--surface-color);
  border-left: 1px solid var(--surface-border);
  box-shadow: var(--shadow-lg);
  display: flex;
  flex-direction: column;
  transform: translateX(100%);
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.app-drawer.open .drawer-panel {
  transform: translateX(0);
}

.drawer-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 20px;
  border-bottom: 1px solid var(--surface-border);
}

.drawer-title-group {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text-main);
}

.drawer-title-group h3 {
  font-size: 1.15rem;
}

.btn-drawer-close {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: transparent;
  border: none;
  border-radius: var(--radius-md);
  color: var(--text-muted);
  font-size: 1.2rem;
  cursor: pointer;
  transition: background-color 0.2s;
}

.btn-drawer-close:hover {
  background-color: var(--surface-color-alt);
  color: var(--text-main);
}

.drawer-body {
  flex: 1;
  overflow-y: auto;
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.drawer-empty-state {
  text-align: center;
  padding: 40px 20px;
}

.empty-icon {
  font-size: 2.5rem;
  margin-bottom: 12px;
}

.drawer-empty-state h4 {
  font-size: 1.1rem;
  margin-bottom: 8px;
}

.drawer-empty-state p {
  font-size: 0.88rem;
  line-height: 1.6;
}

/* Saved Sentences List */
.saved-lesson-group {
  margin-bottom: 16px;
}

.group-lesson-title {
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--primary-light);
  margin-bottom: 8px;
  font-weight: 700;
}

.group-lesson-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--primary-light);
  text-decoration: none;
  transition: all 0.18s ease;
}

.group-lesson-link:hover {
  color: #FFFFFF;
  transform: translateX(2px);
}

.saved-sentence-card {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
  background-color: var(--bg-color);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-md);
  padding: 12px 14px;
  margin-bottom: 8px;
  transition: border-color 0.2s;
}

.saved-sentence-card:hover {
  border-color: var(--surface-border-hover);
}

.saved-card-text .saved-en {
  color: var(--text-main);
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 4px;
}

.saved-card-text .saved-kr {
  color: var(--text-muted);
  font-size: 0.85rem;
}

.btn-delete-sentence {
  background: transparent;
  border: none;
  color: var(--text-subtle);
  cursor: pointer;
  padding: 4px;
  border-radius: var(--radius-sm);
  transition: all 0.2s;
}

.btn-delete-sentence:hover {
  color: var(--accent-rose);
  background: rgba(244, 63, 94, 0.1);
}

/* History Timeline */
.history-item-card {
  background-color: var(--bg-color);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-md);
  padding: 16px;
  margin-bottom: 12px;
}

.history-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 8px;
}

.history-badge {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--accent-emerald);
}

.history-date {
  font-size: 0.75rem;
  color: var(--text-subtle);
}

.history-title {
  font-size: 1rem;
  color: var(--text-main);
  margin-bottom: 12px;
}

/* ==========================================================================
   All Lessons Catalog Section (Cards View)
   ========================================================================== */
.lessons-catalog-section {
  padding: 44px 0 64px;
  scroll-margin-top: 80px;
}

.section-header-catalog {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 36px;
}

.catalog-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  background: rgba(99, 102, 241, 0.12);
  border: 1px solid rgba(99, 102, 241, 0.35);
  border-radius: var(--radius-full);
  color: var(--primary-light);
  font-size: 0.85rem;
  font-weight: 700;
  margin-bottom: 14px;
}

.catalog-title {
  font-size: 2.1rem;
  font-weight: 800;
  color: #FFFFFF;
  letter-spacing: -0.02em;
  margin-bottom: 12px;
}

.catalog-subtitle {
  font-size: 1rem;
  color: var(--text-muted);
  line-height: 1.6;
  word-break: keep-all;
}

.lessons-cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 24px;
}

.lesson-catalog-card {
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  background: var(--surface-color);
  border: 1.5px solid var(--surface-border);
  border-radius: var(--radius-lg);
  padding: 24px;
  transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
  box-shadow: 0 10px 28px rgba(0, 0, 0, 0.25);
  color: inherit;
}

.lesson-catalog-card:hover {
  transform: translateY(-4px);
  border-color: var(--primary-light);
  box-shadow: 0 18px 45px rgba(0, 0, 0, 0.45), 0 0 24px var(--primary-glow);
}

.lesson-card-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 16px;
}

.lesson-card-badges {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.lesson-card-icon {
  font-size: 2.2rem;
  line-height: 1;
  width: 52px;
  height: 52px;
  border-radius: var(--radius-md);
  background: var(--bg-color);
  border: 1.5px solid var(--surface-border);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.lesson-card-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: #FFFFFF;
  margin-bottom: 8px;
  line-height: 1.35;
}

.lesson-card-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.55;
  margin-bottom: 18px;
  word-break: keep-all;
}

.lesson-card-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  padding-top: 14px;
  border-top: 1px solid var(--surface-border);
  margin-bottom: 20px;
  font-size: 0.8rem;
  color: var(--text-subtle);
}

.meta-pill {
  display: inline-flex;
  align-items: center;
  gap: 5px;
}

.lesson-card-btn {
  width: 100%;
  padding: 12px 18px;
  border-radius: var(--radius-md);
  font-size: 0.95rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  text-decoration: none;
  transition: all 0.2s ease;
}

/* ==========================================================================
   Mobile Responsive Navigation & Cards
   ========================================================================== */
@media (max-width: 640px) {
  .nav-inner {
    padding: 0 12px;
    gap: 8px;
  }

  .brand-logo {
    width: 38px;
    height: 38px;
  }

  .brand-name {
    font-size: 1.05rem;
  }

  /* On mobile: Hide all button text labels and show ONLY icons! */
  .nav-btn-label {
    display: none !important;
  }

  .btn-nav-action {
    padding: 6px;
    width: 40px;
    height: 40px;
    min-width: 40px;
    justify-content: center;
    border-radius: var(--radius-full);
    background: rgba(255, 255, 255, 0.05);
  }

  .btn-nav-action:hover {
    background: rgba(255, 255, 255, 0.12);
  }

  .nav-badge {
    position: absolute;
    top: 2px;
    right: 2px;
    min-width: 16px;
    height: 16px;
    font-size: 0.65rem;
    padding: 0 3px;
  }

  .history-unlocked-dot {
    top: 4px;
    right: 4px;
  }

  .lessons-cards-grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .catalog-title {
    font-size: 1.75rem;
  }
}

@media (max-width: 380px) {
  .brand-name {
    display: none;
  }

  .nav-right-actions {
    gap: 4px;
  }
}

/* ==========================================================================
   App Footer & Creative Commons (CC BY 4.0) License Styles
   ========================================================================== */
.app-footer {
  background-color: var(--surface-color);
  border-top: 1px solid var(--surface-border);
  padding: 48px 20px 40px;
  margin-top: 64px;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.footer-container {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.footer-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 20px;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.footer-logo-row {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.footer-logo-icon {
  font-size: 1.25rem;
}

.footer-title {
  font-size: 1.2rem;
  font-weight: 800;
  color: #FFFFFF;
  letter-spacing: -0.01em;
}

.footer-badge {
  font-size: 0.72rem;
  font-weight: 800;
  text-transform: uppercase;
  background: rgba(99, 102, 241, 0.18);
  color: #A5B4FC;
  border: 1px solid rgba(99, 102, 241, 0.35);
  padding: 2px 7px;
  border-radius: var(--radius-full);
}

.footer-tagline {
  font-size: 0.88rem;
  color: var(--text-subtle);
}

.footer-license-box {
  display: flex;
  align-items: center;
}

.cc-license-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(15, 23, 42, 0.6);
  border: 1px solid var(--surface-border);
  padding: 8px 14px;
  border-radius: var(--radius-md);
  color: #E2E8F0;
  text-decoration: none;
  font-weight: 700;
  font-size: 0.85rem;
  transition: all 0.2s ease;
}

.cc-license-badge:hover {
  border-color: var(--primary-light);
  color: #FFFFFF;
  background: rgba(99, 102, 241, 0.12);
}

.cc-icon {
  color: #A5B4FC;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.06);
  padding-top: 20px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-license-text {
  font-size: 0.84rem;
  line-height: 1.6;
  color: var(--text-subtle);
}

.footer-license-text a {
  color: var(--primary-light);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.footer-license-text a:hover {
  color: #FFFFFF;
}

.footer-copyright {
  font-size: 0.8rem;
  color: var(--text-subtle);
}

@media (max-width: 640px) {
  .app-footer {
    padding: 36px 16px 28px;
    margin-top: 48px;
  }

  .footer-top {
    flex-direction: column;
    align-items: flex-start;
  }
}