:root {
  --bg-primary: #f8fafc;
  --bg-card: #ffffff;
  --bg-subtle: #f1f5f9;
  --bg-header: #ffffff;
  --border-color: #e2e8f0;
  --border-card: #e2e8f0;
  --text-primary: #0f172a;
  --text-secondary: #334155;
  --text-muted: #64748b;
  --accent: #2563eb;
  --accent-light: #eff6ff;
  --accent-hover: #1d4ed8;
  --accent-gold: #d97706;
  --success: #16a34a;
  --success-light: #f0fdf4;
  --danger: #dc2626;
  --word-highlight: rgba(37, 99, 235, 0.12);
  --word-active: #2563eb;
  --card-radius: 16px;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.08), 0 2px 4px -1px rgba(0, 0, 0, 0.04);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  --bottom-bar-height: 60px;
  --safe-bottom: env(safe-area-inset-bottom, 12px);
  --font-en: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-mm: 'Padauk', 'Pyidaungsu', 'Myanmar3', sans-serif;
  --font-scale: 1;
}

body.theme-dark {
  --bg-primary: #090d16;
  --bg-card: #131b2e;
  --bg-subtle: #1a253d;
  --bg-header: #0e1526;
  --border-color: #22304f;
  --border-card: #243559;
  --text-primary: #f8fafc;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  --accent: #3b82f6;
  --accent-light: rgba(59, 130, 246, 0.15);
  --accent-hover: #60a5fa;
  --accent-gold: #f59e0b;
  --success: #22c55e;
  --success-light: rgba(34, 197, 94, 0.15);
  --danger: #ef4444;
  --word-highlight: rgba(96, 165, 250, 0.22);
  --word-active: #3b82f6;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.5);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5);
}

/* Base Styles */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-en);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  padding-bottom: calc(var(--bottom-bar-height) + var(--safe-bottom) + 24px);
  transition: background-color 0.25s ease, color 0.25s ease;
  overflow-x: hidden;
}

/* Header */
.app-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background-color: var(--bg-header);
  border-bottom: 1px solid var(--border-color);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: var(--shadow-sm);
  padding: 10px 14px 6px;
}

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

.badge-row {
  display: flex;
  gap: 6px;
  align-items: center;
  margin-bottom: 2px;
}

.badge-code {
  background: var(--accent);
  color: #ffffff;
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.5px;
  padding: 2px 7px;
  border-radius: 6px;
}

.badge-pill {
  background: var(--accent-light);
  color: var(--accent);
  border: 1px solid var(--accent);
  font-size: 10px;
  font-weight: 700;
  padding: 2px 7px;
  border-radius: 6px;
}

.app-title {
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--text-primary);
  letter-spacing: -0.3px;
}

.header-actions {
  display: flex;
  gap: 8px;
}

.icon-btn {
  background: var(--bg-subtle);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  width: 36px;
  height: 36px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.2s ease;
}

.icon-btn:active {
  transform: scale(0.92);
}

/* Study Mode Selector */
.study-mode-container {
  margin-bottom: 8px;
}

.segmented-control {
  display: flex;
  background: var(--bg-subtle);
  border-radius: 12px;
  padding: 3px;
  border: 1px solid var(--border-color);
}

.seg-btn {
  flex: 1;
  padding: 8px 6px;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-size: 0.78rem;
  font-weight: 700;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.2s ease;
  white-space: nowrap;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
}

.seg-btn.active {
  background: var(--bg-card);
  color: var(--accent);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.badge-count {
  background: var(--accent);
  color: #fff;
  font-size: 9px;
  padding: 1px 5px;
  border-radius: 10px;
}

/* Header Toolbar: Search + Lang */
.header-toolbar {
  display: flex;
  gap: 8px;
  margin-bottom: 8px;
}

.search-input-wrap {
  position: relative;
  flex: 1;
  display: flex;
  align-items: center;
  background: var(--bg-subtle);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  padding: 0 10px;
  height: 36px;
}

.search-icon {
  font-size: 13px;
  color: var(--text-muted);
  margin-right: 6px;
}

.search-input-wrap input {
  width: 100%;
  border: none;
  background: transparent;
  color: var(--text-primary);
  font-size: 0.85rem;
  outline: none;
}

.btn-clear {
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 16px;
  cursor: pointer;
  padding: 2px 4px;
}

.lang-pill {
  padding: 0 12px;
  height: 36px;
  background: var(--bg-subtle);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  color: var(--text-secondary);
  font-size: 0.76rem;
  font-weight: 700;
  cursor: pointer;
  white-space: nowrap;
}

/* Category Nav */
.category-nav {
  display: flex;
  gap: 6px;
  overflow-x: auto;
  scrollbar-width: none;
  -webkit-overflow-scrolling: touch;
  padding-bottom: 4px;
}

.category-nav::-webkit-scrollbar {
  display: none;
}

.cat-pill {
  padding: 4px 10px;
  border-radius: 16px;
  border: 1px solid var(--border-color);
  background: var(--bg-subtle);
  color: var(--text-secondary);
  font-size: 0.74rem;
  font-weight: 600;
  white-space: nowrap;
  cursor: pointer;
  transition: all 0.2s ease;
}

.cat-pill.active {
  background: var(--accent);
  color: #ffffff;
  border-color: var(--accent);
}

/* Recall Banner */
.recall-banner {
  max-width: 680px;
  margin: 12px auto 0;
  padding: 0 14px;
}

.banner-content {
  background: var(--accent-light);
  border: 1px solid var(--border-color);
  border-radius: 14px;
  padding: 10px 14px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
}

.banner-title {
  display: block;
  font-size: 0.82rem;
  font-weight: 800;
  color: var(--accent);
  margin-bottom: 2px;
}

.banner-desc {
  font-family: var(--font-mm);
  font-size: 0.76rem;
  color: var(--text-secondary);
  line-height: 1.45;
}

.banner-stat {
  text-align: center;
  background: var(--bg-card);
  padding: 6px 12px;
  border-radius: 10px;
  border: 1px solid var(--border-color);
  flex-shrink: 0;
}

.stat-number {
  display: block;
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--success);
}

.stat-label {
  font-size: 0.65rem;
  color: var(--text-muted);
  text-transform: uppercase;
  font-weight: 700;
}

/* Main Content Area */
.main-content {
  max-width: 680px;
  margin: 12px auto;
  padding: 0 14px;
}

/* Section Card */
.topic-group {
  margin-bottom: 24px;
}

.topic-header {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 12px;
  padding-bottom: 6px;
  border-bottom: 2px solid var(--accent);
}

.topic-icon {
  font-size: 1.3rem;
}

.topic-title {
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--text-primary);
}

.topic-title-mm {
  font-family: var(--font-mm);
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-left: auto;
}

/* Active Recall Flashcard */
.flashcard {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--card-radius);
  margin-bottom: 14px;
  box-shadow: var(--shadow-sm);
  transition: all 0.25s ease;
  overflow: hidden;
}

.flashcard.mastered {
  border-left: 5px solid var(--success);
}

.card-question-box {
  padding: 14px 16px;
  cursor: pointer;
  background: var(--bg-card);
}

.q-label-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 6px;
}

.q-badge {
  background: var(--accent-light);
  color: var(--accent);
  font-size: 0.68rem;
  font-weight: 800;
  padding: 2px 7px;
  border-radius: 6px;
}

.card-hint {
  font-size: 0.72rem;
  color: var(--accent-gold);
  font-weight: 600;
}

.card-question {
  font-size: calc(0.98rem * var(--font-scale));
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.45;
  margin-bottom: 4px;
}

.card-question-mm {
  font-family: var(--font-mm);
  font-size: calc(0.85rem * var(--font-scale));
  color: var(--text-secondary);
  line-height: 1.5;
}

.btn-reveal {
  width: 100%;
  padding: 10px;
  background: var(--bg-subtle);
  border: none;
  border-top: 1px dashed var(--border-color);
  color: var(--accent);
  font-size: 0.82rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  cursor: pointer;
  transition: background-color 0.2s;
  font-family: var(--font-en), var(--font-mm);
}

.btn-reveal:hover {
  background: var(--accent-light);
}

/* Answer Box (Hidden by default, revealed on click) */
.card-answer-box {
  display: none;
  padding: 14px 16px;
  background: var(--bg-subtle);
  border-top: 1px solid var(--border-color);
}

.flashcard.revealed .card-answer-box {
  display: block;
  animation: fadeIn 0.25s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(-4px); }
  to { opacity: 1; transform: translateY(0); }
}

.answer-en {
  font-size: calc(0.95rem * var(--font-scale));
  color: var(--text-primary);
  line-height: 1.6;
  white-space: pre-line;
  margin-bottom: 10px;
}

.answer-mm {
  font-family: var(--font-mm);
  font-size: calc(0.88rem * var(--font-scale));
  color: var(--text-secondary);
  line-height: 1.7;
  white-space: pre-line;
  background: var(--bg-card);
  padding: 10px 12px;
  border-radius: 10px;
  border: 1px solid var(--border-color);
  margin-bottom: 12px;
}

.card-actions-row {
  display: flex;
  gap: 8px;
}

.btn-mark-mastered {
  flex: 1;
  padding: 8px;
  border: 1px solid var(--success);
  background: var(--success-light);
  color: var(--success);
  border-radius: 8px;
  font-size: 0.78rem;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.2s;
}

.btn-mark-mastered.active {
  background: var(--success);
  color: #fff;
}

.btn-card-audio {
  padding: 8px 12px;
  border: 1px solid var(--border-color);
  background: var(--bg-card);
  border-radius: 8px;
  font-size: 0.85rem;
  cursor: pointer;
}

/* Summary Bullet Cards */
.summary-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--card-radius);
  padding: 16px;
  margin-bottom: 14px;
  box-shadow: var(--shadow-sm);
}

.bullet-item {
  margin-bottom: 14px;
  padding-bottom: 12px;
  border-bottom: 1px dashed var(--border-color);
}

.bullet-item:last-child {
  margin-bottom: 0;
  padding-bottom: 0;
  border-bottom: none;
}

.bullet-en {
  font-size: calc(0.96rem * var(--font-scale));
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.5;
  margin-bottom: 4px;
}

.bullet-mm {
  font-family: var(--font-mm);
  font-size: calc(0.86rem * var(--font-scale));
  color: var(--text-secondary);
  line-height: 1.6;
}

/* Full Note view */
.full-note-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--card-radius);
  padding: 16px;
  margin-bottom: 16px;
}

/* Interactive Clickable Words */
.word {
  display: inline-block;
  cursor: pointer;
  border-radius: 4px;
  padding: 0 1px;
  transition: all 0.15s ease;
}

.word:hover {
  background-color: var(--word-highlight);
  color: var(--accent);
}

.word.active-word {
  background-color: var(--word-active) !important;
  color: #ffffff !important;
  border-radius: 4px;
  padding: 0 3px;
}

/* Language view toggles */
body.view-en-only .card-question-mm,
body.view-en-only .answer-mm,
body.view-en-only .bullet-mm,
body.view-en-only .topic-title-mm {
  display: none !important;
}

body.view-mm-only .card-question,
body.view-mm-only .answer-en,
body.view-mm-only .bullet-en {
  display: none !important;
}

/* Word Bottom Sheet */
.sheet-backdrop {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0, 0, 0, 0.4);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  z-index: 90;
}

.bottom-sheet {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  max-width: 580px;
  margin: 0 auto;
  background: var(--bg-card);
  border-top-left-radius: 24px;
  border-top-right-radius: 24px;
  box-shadow: 0 -8px 30px rgba(0, 0, 0, 0.25);
  z-index: 100;
  transform: translateY(105%);
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  max-height: 85vh;
  overflow-y: auto;
  padding: 8px 18px calc(24px + var(--safe-bottom));
}

.bottom-sheet.open {
  transform: translateY(0);
}

.sheet-handle-bar {
  display: flex;
  justify-content: center;
  padding: 6px 0 10px;
}

.sheet-handle {
  width: 36px;
  height: 4px;
  background: var(--border-color);
  border-radius: 2px;
}

.sheet-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 12px;
}

.word-title-row {
  display: flex;
  align-items: center;
  gap: 8px;
}

.sheet-word {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text-primary);
}

.badge-pos {
  background: var(--accent-light);
  color: var(--accent);
  border: 1px solid var(--accent);
  font-size: 0.68rem;
  font-weight: 700;
  padding: 2px 6px;
  border-radius: 6px;
  text-transform: uppercase;
}

.sheet-phonetic {
  font-size: 0.8rem;
  color: var(--text-muted);
  font-style: italic;
}

.sheet-actions {
  display: flex;
  gap: 6px;
}

.icon-btn-circle {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: 1px solid var(--border-color);
  background: var(--bg-subtle);
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}

.star-btn {
  background: none;
  border: none;
  font-size: 1.25rem;
  cursor: pointer;
}

.star-btn.starred {
  filter: drop-shadow(0 0 3px gold);
}

.meaning-box {
  background: var(--accent-light);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 12px 14px;
  margin-bottom: 10px;
}

.field-label {
  display: block;
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  margin-bottom: 4px;
}

.burmese-meaning {
  font-family: var(--font-mm);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.55;
}

.context-box {
  background: var(--bg-subtle);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 10px 12px;
  margin-bottom: 14px;
}

.context-text {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.45;
}

.btn-secondary {
  width: 100%;
  padding: 9px;
  background: var(--bg-subtle);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  color: var(--text-primary);
  font-weight: 600;
  cursor: pointer;
}

/* Modals */
.modal-backdrop {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  z-index: 110;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
}

.modal-card {
  background: var(--bg-card);
  border-radius: 20px;
  width: 100%;
  max-width: 480px;
  max-height: 75vh;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--border-color);
  overflow: hidden;
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 16px;
  border-bottom: 1px solid var(--border-color);
}

.modal-body {
  padding: 14px;
  overflow-y: auto;
  flex: 1;
}

.vocab-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 8px 12px;
  background: var(--bg-subtle);
  border-radius: 8px;
  margin-bottom: 6px;
}

.vocab-word {
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--accent);
}

.vocab-mm {
  font-family: var(--font-mm);
  font-size: 0.85rem;
  color: var(--text-secondary);
}

/* Bottom Nav */
.bottom-nav {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: var(--bottom-bar-height);
  background: var(--bg-header);
  border-top: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-around;
  padding-bottom: var(--safe-bottom);
  z-index: 50;
  box-shadow: 0 -2px 10px rgba(0, 0, 0, 0.05);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.nav-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  flex: 1;
  padding: 4px 0;
  transition: all 0.2s ease;
}

.nav-item.active {
  color: var(--accent);
}

.nav-icon {
  font-size: 1.2rem;
  margin-bottom: 2px;
}

.nav-label {
  font-size: 0.68rem;
  font-weight: 700;
}

/* Audio Toast */
.audio-toast {
  position: fixed;
  bottom: calc(var(--bottom-bar-height) + var(--safe-bottom) + 12px);
  left: 50%;
  transform: translateX(-50%);
  background: var(--text-primary);
  color: var(--bg-primary);
  padding: 8px 16px;
  border-radius: 24px;
  display: flex;
  align-items: center;
  gap: 10px;
  box-shadow: var(--shadow-lg);
  z-index: 80;
  font-size: 0.82rem;
  font-weight: 600;
}

.btn-toast-stop {
  background: var(--danger);
  color: #fff;
  border: none;
  padding: 2px 8px;
  border-radius: 10px;
  font-size: 0.72rem;
  cursor: pointer;
}

.hidden {
  display: none !important;
}

.empty-state {
  text-align: center;
  color: var(--text-muted);
  padding: 24px 10px;
  font-family: var(--font-mm);
  font-size: 0.88rem;
}

@media (max-width: 480px) {
  html {
    font-size: 15px;
  }
}