@import url('https://fonts.googleapis.com/css2?family=Nunito:wght@400;600;700;800&display=swap');

:root {
  --bg: #fdf6ee;
  --bg-warm: #fff8f0;
  --text: #4a3728;
  --text-light: #8b7355;
  --accent: #ff9a6c;
  --accent-hover: #ff7f45;
  --success: #7ecfa0;
  --error: #f0857a;
  --baby-pink: #ffd4d4;
  --baby-blue: #d4e8ff;
  --baby-yellow: #fff4d4;
  --baby-green: #d4f5e0;
  --baby-purple: #e8d4ff;
  --shadow: 0 4px 20px rgba(74, 55, 40, 0.08);
  --shadow-lg: 0 8px 40px rgba(74, 55, 40, 0.12);
  --radius: 20px;
  --radius-sm: 12px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
  font-family: 'Nunito', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  -webkit-tap-highlight-color: transparent;
}

#app {
  max-width: 520px;
  margin: 0 auto;
  min-height: 100vh;
}

/* ===== Animations ===== */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}
.fade-in { animation: fadeIn 0.35s ease; }

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

/* ===== Home Page ===== */
.home-page {
  padding: 40px 24px;
  min-height: 100vh;
  background: linear-gradient(180deg, var(--baby-yellow) 0%, var(--bg) 50%);
}

.home-header {
  text-align: center;
  margin-bottom: 40px;
}

.home-icon {
  font-size: 72px;
  margin-bottom: 16px;
  animation: float 3s ease-in-out infinite;
}

.home-page h1 {
  font-size: 32px;
  font-weight: 800;
}

.home-subtitle {
  font-size: 16px;
  color: var(--text-light);
  font-weight: 600;
  margin-bottom: 12px;
}

.home-desc {
  font-size: 14px;
  color: var(--text-light);
  line-height: 1.7;
}

/* Level Cards */
.level-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 24px;
}

.level-card {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 18px 20px;
  background: white;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  cursor: pointer;
  transition: all 0.2s;
}

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

.level-card.locked {
  opacity: 0.5;
  cursor: not-allowed;
}

.level-badge {
  width: 48px;
  height: 48px;
  border-radius: 14px;
  background: var(--accent);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  font-weight: 800;
  flex-shrink: 0;
}

.level-card.locked .level-badge {
  background: #ccc;
}

.level-info {
  flex: 1;
}

.level-info h3 {
  font-size: 16px;
  font-weight: 700;
}

.level-info p {
  font-size: 12px;
  color: var(--text-light);
  margin-top: 2px;
}

.level-arrow {
  font-size: 20px;
  color: var(--accent);
  font-weight: 700;
}

.level-lock {
  font-size: 18px;
}

/* Mastered Entry */
.mastered-entry {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 16px 20px;
  background: white;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  cursor: pointer;
  transition: all 0.2s;
  font-weight: 700;
  font-size: 15px;
}

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

.mastered-icon { font-size: 22px; }

.mastered-count {
  margin-left: auto;
  color: var(--text-light);
  font-weight: 600;
  font-size: 14px;
}

/* ===== Page Header ===== */
.page-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 20px;
  background: white;
  box-shadow: 0 2px 8px rgba(0,0,0,0.05);
  position: sticky;
  top: 0;
  z-index: 10;
}

.page-header h2 {
  font-size: 17px;
  font-weight: 700;
}

.header-info {
  font-size: 13px;
  color: var(--text-light);
  font-weight: 600;
}

.btn-back {
  width: 38px;
  height: 38px;
  border: none;
  background: var(--bg);
  border-radius: 12px;
  font-size: 18px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.2s;
}

.btn-back:hover { background: #eee; }

/* ===== Scene Grid ===== */
.scene-list-page {
  min-height: 100vh;
}

.scene-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  padding: 20px;
}

.scene-card {
  background: white;
  border-radius: var(--radius-sm);
  padding: 20px 16px;
  text-align: center;
  box-shadow: var(--shadow);
  cursor: pointer;
  transition: all 0.2s;
}

.scene-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
}

.scene-card.done {
  background: var(--baby-green);
}

.scene-card-icon {
  font-size: 36px;
  margin-bottom: 8px;
}

.scene-card-name {
  font-size: 14px;
  font-weight: 700;
  margin-bottom: 8px;
}

.scene-card-progress {
  display: flex;
  align-items: center;
  gap: 8px;
}

.mini-progress-bar {
  flex: 1;
  height: 5px;
  background: #eee;
  border-radius: 3px;
  overflow: hidden;
}

.mini-progress-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 3px;
  transition: width 0.4s ease;
}

.scene-card-count {
  font-size: 11px;
  color: var(--text-light);
  font-weight: 600;
  flex-shrink: 0;
}

/* ===== Learn Page ===== */
.learn-page {
  min-height: 100vh;
  background: var(--bg-warm);
}

/* Group Tabs */
.group-tabs-wrap {
  position: sticky;
  top: 66px;
  z-index: 9;
  background: var(--bg-warm);
  padding: 8px 16px;
  border-bottom: 1px solid #f0ebe4;
}

.group-tabs {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  scrollbar-width: none;
  -webkit-overflow-scrolling: touch;
}

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

.group-tab {
  flex-shrink: 0;
  padding: 6px 14px;
  border: 2px solid #e8e0d6;
  background: white;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 700;
  color: var(--text-light);
  cursor: pointer;
  transition: all 0.2s;
  font-family: inherit;
}

.group-tab:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.group-tab.active {
  background: var(--accent);
  border-color: var(--accent);
  color: white;
}

.learn-content {
  padding: 16px 16px 40px;
}

/* Group */
.learn-group {
  margin-bottom: 24px;
}

.group-title {
  font-size: 13px;
  font-weight: 800;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  padding: 8px 4px;
  border-bottom: 2px solid var(--accent);
  margin-bottom: 4px;
}

/* Word/Sentence Row */
.word-list {
  display: flex;
  flex-direction: column;
}

.learn-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 14px;
  background: white;
  border-bottom: 1px solid #f0ebe4;
  cursor: pointer;
  transition: background 0.15s;
}

.learn-row:first-child {
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
}

.learn-row:last-child {
  border-bottom: none;
  border-radius: 0 0 var(--radius-sm) var(--radius-sm);
}

.learn-row:only-child {
  border-radius: var(--radius-sm);
}

.learn-row:active {
  background: var(--baby-yellow);
}

.learn-row.is-mastered {
  opacity: 0.5;
}

.row-left {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: 1;
  min-width: 0;
}

.item-emoji {
  font-size: 18px;
  flex-shrink: 0;
  margin-left: 4px;
}

.row-en {
  font-size: 17px;
  font-weight: 700;
  color: var(--text);
  flex-shrink: 0;
}

.row-cn {
  font-size: 15px;
  color: var(--text-light);
  margin-left: 6px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.row-right {
  display: flex;
  align-items: center;
  gap: 4px;
  flex-shrink: 0;
}

.btn-speak {
  width: 36px;
  height: 36px;
  border: none;
  background: transparent;
  font-size: 18px;
  cursor: pointer;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s;
  color: var(--accent);
}

.btn-speak:hover {
  background: var(--baby-yellow);
}

.btn-speak svg {
  pointer-events: none;
}

.btn-master, .btn-master-sentence {
  width: 36px;
  height: 36px;
  border: none;
  background: transparent;
  font-size: 18px;
  cursor: pointer;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.15s;
}

.btn-master:hover, .btn-master-sentence:hover {
  background: var(--baby-green);
}

.btn-master.mastered, .btn-master-sentence.mastered {
  background: var(--baby-green);
}

.btn-unmaster, .btn-unmaster-sentence {
  width: 36px;
  height: 36px;
  border: none;
  background: transparent;
  font-size: 16px;
  cursor: pointer;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s;
}

.btn-unmaster:hover, .btn-unmaster-sentence:hover {
  background: var(--baby-pink);
}

/* Sentence rows */
.sentence-section {
  margin-top: 4px;
  border-top: 2px dashed #f0ebe4;
}

.sentence-row .row-left {
  flex-direction: column;
  align-items: flex-start;
  gap: 2px;
}

.sentence-row .row-en {
  font-size: 17px;
  font-weight: 600;
  white-space: normal;
  word-break: break-word;
  line-height: 1.4;
}

.sentence-row .row-cn {
  font-size: 15px;
  margin-left: 0;
  white-space: normal;
  word-break: break-word;
  line-height: 1.4;
}

/* Clickable words in sentences */
.clickable-word {
  cursor: pointer;
  border-radius: 3px;
  transition: background 0.15s;
  text-decoration-line: underline;
  text-decoration-style: dotted;
  text-decoration-color: #d0c8be;
  text-underline-offset: 3px;
}

.clickable-word:active {
  background: var(--baby-yellow);
}

/* Mastered collapse */
.mastered-section {
  margin-top: 4px;
}

.mastered-summary {
  font-size: 12px;
  color: var(--text-light);
  font-weight: 600;
  padding: 8px 14px;
  cursor: pointer;
  background: #f5f0ea;
  border-radius: var(--radius-sm);
  list-style: none;
  transition: background 0.15s;
}

.mastered-summary:hover {
  background: #ede6dc;
}

.mastered-summary::-webkit-details-marker { display: none; }

.mastered-list {
  margin-top: 4px;
}

/* ===== Mastered Page ===== */
.mastered-page {
  min-height: 100vh;
  background: var(--bg-warm);
}

.mastered-content {
  padding: 16px 16px 40px;
}

.mastered-scene-group {
  margin-bottom: 20px;
}

.mastered-scene-title {
  font-size: 14px;
  font-weight: 800;
  color: var(--text);
  padding: 8px 4px;
  border-bottom: 2px solid var(--baby-green);
  margin-bottom: 4px;
}

/* Empty State */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 50vh;
  text-align: center;
  padding: 40px;
}

.empty-icon {
  font-size: 60px;
  margin-bottom: 16px;
}

.empty-state p {
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 8px;
}

.empty-hint {
  font-size: 14px !important;
  color: var(--text-light);
  font-weight: 400 !important;
}

/* ===== Responsive ===== */
@media (max-width: 380px) {
  .scene-grid { gap: 8px; padding: 12px; }
  .scene-card { padding: 14px 10px; }
  .row-en { font-size: 14px; }
  .row-cn { font-size: 12px; }
}

/* ===== Word Detail Sheet ===== */
.word-detail-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.35);
  z-index: 100;
  animation: overlayIn 0.2s ease;
}

@keyframes overlayIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

.word-detail-sheet {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  max-width: 520px;
  margin: 0 auto;
  background: white;
  border-radius: 20px 20px 0 0;
  z-index: 101;
  max-height: 80vh;
  overflow-y: auto;
  animation: sheetUp 0.25s ease;
  padding: 0 24px 32px;
}

@keyframes sheetUp {
  from { transform: translateY(100%); }
  to { transform: translateY(0); }
}

.sheet-handle {
  display: flex;
  justify-content: center;
  padding: 12px 0 8px;
  cursor: pointer;
  position: sticky;
  top: 0;
  background: white;
  z-index: 1;
}

.sheet-handle::after {
  content: '';
  width: 40px;
  height: 4px;
  background: #d0c8be;
  border-radius: 2px;
}

.detail-header {
  text-align: center;
  margin-bottom: 8px;
}

.detail-emoji {
  font-size: 40px;
  margin-bottom: 4px;
}

.detail-word {
  font-size: 28px;
  font-weight: 800;
  color: var(--text);
  margin-bottom: 2px;
}

.detail-phonetic {
  font-size: 15px;
  color: var(--accent);
  font-weight: 600;
  margin-bottom: 2px;
}

.detail-pos {
  font-size: 13px;
  color: var(--text);
  background: var(--baby-blue);
  display: inline-block;
  padding: 2px 10px;
  border-radius: 10px;
  font-weight: 700;
  margin-bottom: 4px;
}

.detail-cn {
  font-size: 17px;
  color: var(--text-light);
  font-weight: 600;
}

.detail-play-btns {
  display: flex;
  gap: 12px;
  justify-content: center;
  margin: 10px 0;
}

.detail-play-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  border: 2px solid var(--accent);
  background: white;
  border-radius: 24px;
  font-size: 14px;
  font-weight: 700;
  color: var(--accent);
  cursor: pointer;
  font-family: inherit;
  transition: all 0.15s;
}

.detail-play-btn:active {
  background: var(--accent);
  color: white;
}

.detail-section-title {
  font-size: 13px;
  font-weight: 800;
  color: var(--text-light);
  letter-spacing: 0.5px;
  padding: 12px 0 8px;
  border-bottom: 2px solid #f0ebe4;
  margin-bottom: 4px;
}

.detail-example-row {
  padding: 10px 0;
  border-bottom: 1px solid #f5f0ea;
  cursor: pointer;
  transition: background 0.15s;
}

.detail-example-row:active {
  background: var(--baby-yellow);
}

.detail-example-en {
  font-size: 16px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 2px;
}

.detail-example-cn {
  font-size: 14px;
  color: var(--text-light);
}

.detail-synonyms {
  margin-top: 4px;
}

.detail-synonym-tag {
  display: inline-block;
  padding: 4px 12px;
  margin: 4px 4px 4px 0;
  background: var(--baby-purple);
  border-radius: 12px;
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
  cursor: pointer;
}

.detail-synonym-tag:active {
  opacity: 0.7;
}

.detail-diff {
  margin-top: 8px;
  padding: 10px 14px;
  background: var(--baby-yellow);
  border-radius: 12px;
  font-size: 14px;
  line-height: 1.6;
  color: var(--text);
}

/* ===== Undo Toast ===== */
.undo-toast {
  position: fixed;
  bottom: 28px;
  left: 50%;
  transform: translateX(-50%);
  background: rgba(74, 55, 40, 0.92);
  color: white;
  padding: 10px 16px;
  border-radius: 24px;
  font-size: 14px;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 12px;
  z-index: 200;
  animation: toastIn 0.2s ease;
  max-width: 340px;
  box-shadow: 0 4px 16px rgba(0,0,0,0.2);
}

.undo-toast.hiding {
  animation: toastOut 0.3s ease forwards;
}

.undo-btn {
  background: var(--accent);
  color: white;
  border: none;
  padding: 5px 14px;
  border-radius: 12px;
  font-weight: 700;
  font-size: 13px;
  cursor: pointer;
  font-family: inherit;
  flex-shrink: 0;
}

@keyframes toastIn {
  from { opacity: 0; transform: translateX(-50%) translateY(20px); }
  to { opacity: 1; transform: translateX(-50%) translateY(0); }
}

@keyframes toastOut {
  from { opacity: 1; transform: translateX(-50%) translateY(0); }
  to { opacity: 0; transform: translateX(-50%) translateY(20px); }
}