/* ===== Reset & Base ===== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --bg: #f0f2f8;
  --bg-card: #ffffff;
  --text: #1a1d2e;
  --text-muted: #8b8fa7;
  --accent: #5b6bdf;
  --accent-hover: #4a59c9;
  --accent-light: rgba(91, 107, 223, 0.08);
  --green: #3cc68a;
  --green-hover: #2eb87a;
  --green-light: rgba(60, 198, 138, 0.08);
  --red: #ef5565;
  --orange: #f5a623;
  --border: #e4e7f0;
  --shadow: 0 4px 24px rgba(30, 40, 90, 0.08), 0 1px 3px rgba(30, 40, 90, 0.04);
  --shadow-lg: 0 20px 60px rgba(30, 40, 90, 0.12), 0 4px 12px rgba(30, 40, 90, 0.06);
  --shadow-card: 0 8px 40px rgba(30, 40, 90, 0.10), 0 2px 6px rgba(30, 40, 90, 0.04);
  --radius: 20px;
  --radius-sm: 10px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;

  --card-max-w: 92vw;
  --front-font: 2.2rem;
  --front-pad: 40px 28px;
  --back-pad: 22px 24px;
  --back-word-font: 1.6rem;
  --container-max-w: 100%;
  --container-pad: 0 16px;
  --btn-font: 0.95rem;
  --btn-pad: 12px 24px;
}

html, body {
  height: 100%;
  overflow: hidden;
}

html {
  font-size: 16px;
}

body {
  font-family: var(--font);
  background: var(--bg);
  background-image:
    radial-gradient(ellipse at 15% 0%, rgba(253, 232, 232, 0.5) 0%, transparent 50%),
    radial-gradient(ellipse at 85% 15%, rgba(227, 238, 251, 0.5) 0%, transparent 50%),
    radial-gradient(ellipse at 50% 100%, rgba(232, 245, 227, 0.5) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 80%, rgba(250, 227, 242, 0.4) 0%, transparent 50%);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
}

/* ===== Confetti Canvas ===== */
#confetti-canvas {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 9999;
}

/* ===== Settings Drawer ===== */
.settings-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.3);
  z-index: 100;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition);
}

.settings-overlay.active {
  opacity: 1;
  pointer-events: auto;
}

.settings-drawer {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  width: 340px;
  max-width: 85vw;
  background: var(--bg-card);
  z-index: 101;
  transform: translateX(-100%);
  transition: transform var(--transition);
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-lg);
  border-right: 1px solid var(--border);
}

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

.settings-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 24px;
  border-bottom: 1px solid var(--border);
}

.settings-header h2 {
  font-size: 1.15rem;
  font-weight: 600;
}

.settings-close {
  width: 32px;
  height: 32px;
  border: none;
  background: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--text-muted);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition);
}

.settings-close:hover {
  background: var(--border);
}

.settings-body {
  flex: 1;
  overflow-y: auto;
  padding: 20px 24px;
}

.setting-item {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 20px;
}

.setting-label {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-muted);
}

.setting-item textarea,
.setting-item select {
  font-family: var(--font);
  font-size: 0.95rem;
  padding: 10px 12px;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg);
  color: var(--text);
  outline: none;
  transition: border-color var(--transition);
  resize: vertical;
}

.setting-item textarea:focus,
.setting-item select:focus {
  border-color: var(--accent);
}

/* Toggle Switch */
.setting-toggle {
  flex-direction: row;
  align-items: center;
  justify-content: space-between;
  position: relative;
  cursor: pointer;
}

.setting-toggle input {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
}

.toggle-slider {
  width: 44px;
  height: 24px;
  background: var(--border);
  border-radius: 12px;
  position: relative;
  flex-shrink: 0;
  transition: background var(--transition);
}

.toggle-slider::after {
  content: '';
  position: absolute;
  top: 2px;
  left: 2px;
  width: 20px;
  height: 20px;
  background: white;
  border-radius: 50%;
  transition: transform var(--transition);
  box-shadow: 0 1px 3px rgba(0,0,0,0.15);
}

.setting-toggle input:checked + .toggle-slider {
  background: var(--accent);
}

.setting-toggle input:checked + .toggle-slider::after {
  transform: translateX(20px);
}

.setting-divider {
  border: none;
  border-top: 1px solid var(--border);
  margin: 16px 0;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: var(--font);
  font-size: var(--btn-font);
  font-weight: 500;
  padding: var(--btn-pad);
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition);
  user-select: none;
  -webkit-tap-highlight-color: transparent;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent), #4a59c9);
  color: white;
  box-shadow: 0 2px 10px rgba(91, 107, 223, 0.2);
}

.btn-primary:hover {
  background: linear-gradient(135deg, var(--accent-hover), #3f4db8);
  box-shadow: 0 4px 14px rgba(91, 107, 223, 0.3);
}

.btn-outline {
  background: transparent;
  color: var(--text-muted);
  border: 1.5px solid var(--border);
}

.btn-outline:hover {
  border-color: var(--text-muted);
  color: var(--text);
}

.btn-block {
  width: 100%;
}

.icon-btn {
  width: 42px;
  height: 42px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1.5px solid var(--border);
  background: var(--bg-card);
  cursor: pointer;
  border-radius: 12px;
  color: var(--text-muted);
  transition: all var(--transition);
  -webkit-tap-highlight-color: transparent;
  flex-shrink: 0;
}

.icon-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
  box-shadow: 0 2px 8px rgba(91, 107, 223, 0.1);
}

/* ===== App Container — fills exactly one viewport ===== */
.app-container {
  max-width: var(--container-max-w);
  margin: 0 auto;
  padding: var(--container-pad);
  height: 100dvh;
  height: 100vh; /* fallback */
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

/* ===== Top Bar ===== */
.top-bar {
  flex-shrink: 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  padding: 10px 0 6px;
}

.stats-bar {
  flex: 1;
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.9rem;
}

#stats-text {
  font-weight: 700;
  font-size: 0.95rem;
}

.stats-learned {
  color: var(--green);
  font-weight: 600;
  font-size: 0.85rem;
  background: var(--green-light);
  padding: 2px 10px;
  border-radius: 20px;
}

.progress-wrap {
  width: 100%;
  height: 5px;
  background: var(--border);
  border-radius: 3px;
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  background: linear-gradient(90deg, #E8707A, #D46BA8, #9B72CF, #5B8FD4, #4DAF9C, #6BBF6B);
  border-radius: 3px;
  transition: width 0.5s ease;
}

/* ===== Loading State ===== */
.loading-state {
  flex: 1;
  min-height: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 24px;
  padding: 40px 0;
}

.skeleton-card {
  width: 100%;
  max-width: var(--card-max-w);
  height: 300px;
  background: var(--bg-card);
  border-radius: var(--radius);
  box-shadow: var(--shadow-card);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 16px;
  padding: 40px;
}

.skeleton-line {
  height: 20px;
  border-radius: 10px;
  background: linear-gradient(90deg, var(--border) 25%, #f0f0eb 50%, var(--border) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
}

.skeleton-line.wide { width: 70%; height: 28px; }
.skeleton-line.narrow { width: 40%; }

@keyframes shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

.loading-text {
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* ===== Empty State ===== */
.empty-state {
  flex: 1;
  min-height: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  gap: 14px;
  padding: 40px 0;
}

.empty-icon {
  font-size: 3.5rem;
  margin-bottom: 8px;
  filter: drop-shadow(0 4px 8px rgba(0,0,0,0.1));
}

.empty-state h2 {
  font-size: 1.4rem;
  font-weight: 700;
}

.empty-state p {
  color: var(--text-muted);
  font-size: 0.95rem;
  max-width: 300px;
  line-height: 1.6;
}

.word-input-list {
  width: 100%;
  max-width: 340px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.word-input-row {
  display: flex;
  gap: 6px;
  align-items: center;
}

.word-input {
  flex: 1;
  padding: 10px 14px;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  background: var(--bg-card);
  color: var(--text);
  outline: none;
  transition: border-color 0.2s;
}

.word-input:focus {
  border-color: var(--accent);
}

.btn-remove-word {
  width: 32px;
  height: 32px;
  border: none;
  background: transparent;
  color: var(--text-muted);
  font-size: 1.2rem;
  cursor: pointer;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s, color 0.15s;
  flex-shrink: 0;
}

.btn-remove-word:hover {
  background: rgba(231, 76, 60, 0.1);
  color: #e74c3c;
}

.btn-add-word {
  max-width: 340px;
  width: 100%;
}

.btn-generate {
  max-width: 340px;
  width: 100%;
  margin-top: 6px;
}

/* ===== Flashcard — fills remaining viewport space ===== */
.card-area {
  flex: 1;
  min-height: 0;
  display: flex;
  align-items: stretch;
  justify-content: center;
  padding: 6px 0;
}

.flashcard {
  width: 100%;
  max-width: var(--card-max-w);
  cursor: pointer;
  outline: none;
  perspective: 1200px;
  -webkit-tap-highlight-color: transparent;
  display: flex;
  flex-direction: column;
}

.flashcard-inner {
  position: relative;
  width: 100%;
  flex: 1;
  transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
  transform-style: preserve-3d;
}

.flashcard.flipped .flashcard-inner {
  transform: rotateY(180deg);
}

.flashcard-front,
.flashcard-back {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  border-radius: var(--radius);
  background: var(--macaron-bg, var(--bg-card));
  box-shadow: var(--shadow-card);
  display: flex;
  flex-direction: column;
  border: 2.5px solid color-mix(in srgb, var(--macaron-accent, var(--accent)) 25%, transparent);
}

.flashcard-front {
  overflow: hidden;
  z-index: 2;
}

/* Scalloped lace top border */
.flashcard-front::before {
  content: '';
  position: absolute;
  top: -1px;
  left: 10px;
  right: 10px;
  height: 12px;
  background:
    radial-gradient(circle at 10px -5px, transparent 10px, var(--macaron-accent, var(--accent)) 10px, var(--macaron-accent, var(--accent)) 12px, transparent 12px)
    repeat-x;
  background-size: 20px 12px;
  border-radius: var(--radius) var(--radius) 0 0;
  opacity: 0.35;
}

/* Scalloped lace bottom border */
.flashcard-front::after {
  content: '';
  position: absolute;
  bottom: -1px;
  left: 10px;
  right: 10px;
  height: 12px;
  background:
    radial-gradient(circle at 10px 17px, transparent 10px, var(--macaron-accent, var(--accent)) 10px, var(--macaron-accent, var(--accent)) 12px, transparent 12px)
    repeat-x;
  background-size: 20px 12px;
  opacity: 0.35;
  z-index: 1;
}

.flashcard-back {
  overflow-x: hidden;
  overflow-y: auto;
  transform: rotateY(180deg);
  -webkit-overflow-scrolling: touch;
}

/* Scalloped lace top border on back */
.flashcard-back::before {
  content: '';
  position: sticky;
  top: -1px;
  left: 10px;
  right: 10px;
  height: 12px;
  flex-shrink: 0;
  background:
    radial-gradient(circle at 10px -5px, transparent 10px, var(--macaron-accent, var(--accent)) 10px, var(--macaron-accent, var(--accent)) 12px, transparent 12px)
    repeat-x;
  background-size: 20px 12px;
  opacity: 0.35;
  z-index: 1;
}


/* Card Badge (learned indicator) */
.card-badge {
  position: absolute;
  top: 16px;
  right: 16px;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 4px 12px;
  border-radius: 20px;
  display: none;
  z-index: 3;
}

.card-badge.show {
  display: flex;
  align-items: center;
  gap: 4px;
}

.card-badge.learned {
  background: var(--green-light);
  color: var(--green);
}

/* Front */
.card-front-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--front-pad);
  gap: 12px;
  position: relative;
  overflow: hidden;
}

.card-front-content::before {
  content: '📖';
  font-size: 1.6rem;
  opacity: 0.3;
}

.card-front-content::after {
  content: '';
  position: absolute;
  bottom: -30px;
  right: -30px;
  width: 120px;
  height: 120px;
  border-radius: 50%;
  background: var(--macaron-accent, var(--accent));
  opacity: 0.06;
}

.card-front-text {
  font-size: var(--front-font);
  font-weight: 800;
  line-height: 1.3;
  text-align: center;
  word-break: break-word;
  letter-spacing: 0.5px;
}

.card-hint {
  flex-shrink: 0;
  text-align: center;
  padding: 10px;
  font-size: 0.82rem;
  color: var(--text-muted);
  border-top: 1px dashed color-mix(in srgb, var(--macaron-accent, var(--border)) 30%, transparent);
  letter-spacing: 0.5px;
}

.card-hint::before {
  content: '👆 ';
}

/* Back */
.card-back-content {
  padding: var(--back-pad);
  flex: 1;
}

.card-word {
  font-size: var(--back-word-font);
  font-weight: 800;
  margin-bottom: 4px;
  color: var(--macaron-accent, var(--accent));
  letter-spacing: 0.3px;
}

.card-phonetic {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 1rem;
  font-family: "Courier New", Courier, monospace;
  color: var(--text-muted);
  margin-bottom: 14px;
  padding-bottom: 10px;
  border-bottom: 1px dashed color-mix(in srgb, var(--macaron-accent, var(--border)) 30%, transparent);
}

.play-btn {
  width: 34px;
  height: 34px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: none;
  background: color-mix(in srgb, var(--macaron-accent, var(--accent)) 12%, transparent);
  color: var(--macaron-accent, var(--accent));
  border-radius: 50%;
  cursor: pointer;
  transition: all var(--transition);
  flex-shrink: 0;
}

.play-btn:hover {
  background: color-mix(in srgb, var(--macaron-accent, var(--accent)) 22%, transparent);
  transform: scale(1.1);
}

.play-btn.playing {
  animation: pulse-play 0.8s ease infinite;
}

@keyframes pulse-play {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.15); }
}

.card-section {
  margin-bottom: 14px;
  padding: 10px 12px;
  border-radius: 8px;
  background: var(--section-bg, transparent);
}

.card-section-label {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--section-color, var(--text-muted));
  margin-bottom: 5px;
}

/* Per-section color theming */
.card-section:has(.card-pos) {
  --section-color: #7B85C9;
  --section-bg: rgba(123, 133, 201, 0.05);
}

.card-section:has(.card-translation) {
  --section-color: #D46BA8;
  --section-bg: rgba(212, 107, 168, 0.06);
}

.card-section:has(.card-definition) {
  --section-color: #5B8FD4;
  --section-bg: rgba(91, 143, 212, 0.05);
}

.card-section:has(.card-synonyms) {
  --section-color: #4DAF9C;
  --section-bg: rgba(77, 175, 156, 0.05);
}

.card-section:has(.card-example) {
  --section-color: #CFA04E;
  --section-bg: rgba(207, 160, 78, 0.05);
}

.card-pos {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.pos-tag {
  font-size: 0.82rem;
  padding: 3px 12px;
  border-radius: 20px;
  background: color-mix(in srgb, var(--macaron-accent, var(--accent)) 10%, transparent);
  color: var(--macaron-accent, var(--accent));
  font-weight: 600;
}

.card-translation {
  font-size: 1.2rem;
  font-weight: 700;
  color: #D46BA8;
  font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  letter-spacing: 1px;
}

.card-definition {
  font-size: 0.95rem;
  line-height: 1.7;
  font-family: Georgia, "Times New Roman", serif;
  color: #3a3f5c;
}

.def-item {
  margin-bottom: 6px;
  padding: 4px 0;
}

.def-item .def-pos {
  font-weight: 700;
  color: var(--macaron-accent, var(--accent));
  font-size: 0.82rem;
  margin-right: 6px;
  background: color-mix(in srgb, var(--macaron-accent, var(--accent)) 10%, transparent);
  padding: 1px 8px;
  border-radius: 4px;
}

.card-synonyms {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.synonym-tag {
  font-size: 0.82rem;
  padding: 3px 12px;
  border-radius: 20px;
  background: var(--green-light);
  color: var(--green);
  font-weight: 600;
}

.card-example {
  font-size: 0.92rem;
  color: #7a6c3a;
  font-style: italic;
  line-height: 1.7;
  font-family: Georgia, "Times New Roman", serif;
}

.example-item {
  margin-bottom: 6px;
  padding: 6px 12px;
  border-left: 3px solid #CFA04E;
  background: rgba(207, 160, 78, 0.06);
  border-radius: 0 6px 6px 0;
}

/* ===== Controls ===== */
.controls {
  flex-shrink: 0;
  padding: 8px 0 12px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.nav-row {
  display: flex;
  align-items: center;
  gap: 12px;
  width: 100%;
  max-width: var(--card-max-w);
}

.btn-nav {
  flex: 1;
  background: var(--bg-card);
  color: var(--text);
  border: 1.5px solid var(--border);
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
  border-radius: var(--radius-sm);
}

.btn-nav:hover {
  border-color: var(--accent);
  color: var(--accent);
  box-shadow: 0 4px 12px rgba(91, 107, 223, 0.1);
}

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

.btn-nav:disabled:hover {
  border-color: var(--border);
  color: var(--text);
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
}

.nav-indicator {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-muted);
  white-space: nowrap;
  min-width: 60px;
  text-align: center;
}

.btn-learned {
  width: 100%;
  max-width: var(--card-max-w);
  background: linear-gradient(135deg, var(--green), #2db87c);
  color: white;
  font-size: 1.05rem;
  font-weight: 600;
  padding: 14px 24px;
  border-radius: 12px;
  box-shadow: 0 4px 16px rgba(60, 198, 138, 0.25);
}

.btn-learned:hover {
  background: linear-gradient(135deg, var(--green-hover), #26a670);
  box-shadow: 0 6px 20px rgba(60, 198, 138, 0.3);
  transform: translateY(-1px);
}

.btn-learned.already-learned {
  background: var(--bg-card);
  color: var(--green);
  border: 1.5px solid var(--green);
  box-shadow: none;
}

.btn-learned.already-learned:hover {
  background: rgba(60, 198, 138, 0.06);
  box-shadow: 0 2px 10px rgba(60, 198, 138, 0.15);
  transform: translateY(-1px);
}

.btn-done {
  width: 100%;
  max-width: var(--card-max-w);
  background: transparent;
  color: var(--accent);
  font-size: 0.95rem;
  font-weight: 600;
  padding: 12px 24px;
  border: 1.5px solid var(--border);
  border-radius: 12px;
}

.btn-done:hover {
  background: var(--accent);
  color: white;
  border-color: var(--accent);
  box-shadow: 0 4px 16px rgba(91, 107, 223, 0.2);
}

/* ===== Summary Modal ===== */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.4);
  z-index: 200;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.modal-overlay.show {
  opacity: 1;
}

.modal-content {
  background: var(--bg-card);
  border-radius: var(--radius);
  padding: 32px;
  max-width: 440px;
  width: 100%;
  box-shadow: var(--shadow-lg);
  transform: translateY(20px) scale(0.95);
  transition: transform 0.3s ease;
  text-align: center;
  border: 1px solid var(--border);
}

.modal-overlay.show .modal-content {
  transform: translateY(0) scale(1);
}

.modal-title {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 24px;
}

.summary-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  margin-bottom: 20px;
}

.summary-stat {
  padding: 16px 12px;
  border-radius: var(--radius-sm);
  background: var(--bg);
  border: 1px solid var(--border);
}

.summary-stat-value {
  display: block;
  font-size: 1.8rem;
  font-weight: 700;
  line-height: 1.2;
}

.summary-stat-label {
  display: block;
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 4px;
}

.summary-stat.learned .summary-stat-value { color: var(--green); }
.summary-stat.remaining .summary-stat-value { color: var(--orange); }
.summary-stat.time .summary-stat-value { color: var(--accent); }

.summary-message {
  font-size: 1rem;
  margin-bottom: 24px;
  padding: 12px;
  border-radius: var(--radius-sm);
  min-height: 20px;
}

.summary-message.perfect {
  background: rgba(92, 184, 92, 0.08);
  color: var(--green);
  font-weight: 600;
}

.modal-actions {
  display: flex;
  gap: 12px;
}

.modal-actions .btn {
  flex: 1;
}

/* ===== Utility ===== */
.hidden {
  display: none !important;
}

/* ===== Animations ===== */
@keyframes bounce-in {
  0% { transform: scale(0.8); opacity: 0; }
  60% { transform: scale(1.05); }
  100% { transform: scale(1); opacity: 1; }
}

.card-area {
  animation: bounce-in 0.4s ease;
}

.btn-learned.pop {
  animation: pop-learned 0.5s ease;
}

@keyframes pop-learned {
  0% { transform: scale(1); }
  30% { transform: scale(0.92); }
  60% { transform: scale(1.08); }
  100% { transform: scale(1); }
}

/* ============================================================
   Responsive: Phone → iPad → Desktop
   ============================================================ */

/* --- Small phone (≤380px) --- */
@media (max-width: 380px) {
  :root {
    --front-font: 1.9rem;
    --front-pad: 24px 18px;
    --back-pad: 16px 16px;
    --back-word-font: 1.3rem;
    --btn-pad: 10px 14px;
    --btn-font: 0.88rem;
  }
  .card-front-content::before { font-size: 1.3rem; }
  .nav-row { gap: 8px; }
  .btn-learned { font-size: 0.95rem; padding: 11px 18px; }
  .btn-done { padding: 10px 18px; font-size: 0.88rem; }
  .controls { gap: 6px; padding: 6px 0 10px; }
  .top-bar { padding: 8px 0 4px; gap: 6px; }
  .card-hint { padding: 8px; font-size: 0.78rem; }
}

/* --- Regular phone (381-599px) — base vars are already set --- */

/* --- Tablet / iPad portrait (min 600px) --- */
@media (min-width: 600px) {
  :root {
    --card-max-w: 520px;
    --front-font: 2.8rem;
    --front-pad: 56px 44px;
    --back-pad: 28px 32px;
    --back-word-font: 1.9rem;
    --container-max-w: 600px;
    --container-pad: 0 28px;
    --btn-font: 1rem;
    --btn-pad: 14px 28px;
  }

  .card-front-content::before { font-size: 2rem; }
  .card-phonetic { font-size: 1.1rem; }
  .card-definition { font-size: 1rem; }
  .card-example { font-size: 0.95rem; }
  .pos-tag, .synonym-tag { font-size: 0.88rem; padding: 4px 14px; }
  .card-section { margin-bottom: 16px; padding: 12px 14px; }
  .card-section-label { font-size: 0.76rem; }
  .play-btn { width: 38px; height: 38px; }
  .nav-indicator { font-size: 1rem; }
  .btn-learned { font-size: 1.1rem; padding: 15px 28px; }
  .icon-btn { width: 46px; height: 46px; }
  #stats-text { font-size: 1rem; }
  .stats-learned { font-size: 0.9rem; }
  .progress-wrap { height: 6px; }
  .top-bar { padding: 14px 0 8px; }
  .controls { padding: 10px 0 16px; gap: 10px; }
  .modal-content { padding: 36px; max-width: 480px; }
  .summary-stat-value { font-size: 2rem; }
}

/* --- iPad landscape / small desktop (min 820px) --- */
@media (min-width: 820px) {
  :root {
    --card-max-w: 580px;
    --front-font: 3.2rem;
    --front-pad: 64px 52px;
    --back-pad: 32px 40px;
    --back-word-font: 2.1rem;
    --container-max-w: 680px;
    --container-pad: 0 32px;
    --btn-font: 1.05rem;
    --btn-pad: 15px 32px;
  }

  .card-front-content::before { font-size: 2.2rem; }
  .card-phonetic { font-size: 1.15rem; gap: 10px; margin-bottom: 18px; padding-bottom: 14px; }
  .card-definition { font-size: 1.05rem; }
  .card-example { font-size: 1rem; }
  .pos-tag, .synonym-tag { font-size: 0.9rem; padding: 4px 16px; }
  .card-section { margin-bottom: 18px; padding: 14px 16px; }
  .card-section-label { font-size: 0.78rem; margin-bottom: 6px; }
  .play-btn { width: 40px; height: 40px; }
  .nav-indicator { font-size: 1.05rem; }
  .btn-learned { font-size: 1.15rem; padding: 16px 32px; }
  .btn-done { font-size: 1.05rem; padding: 14px 28px; }
  .card-hint { padding: 12px; font-size: 0.88rem; }
  .icon-btn { width: 48px; height: 48px; }
  #stats-text { font-size: 1.05rem; }
  .stats-learned { font-size: 0.92rem; padding: 3px 12px; }
  .progress-wrap { height: 7px; }
  .top-bar { padding: 16px 0 10px; }
  .controls { padding: 12px 0 20px; gap: 10px; }
  .modal-content { padding: 40px; max-width: 520px; }
  .summary-stat { padding: 20px 16px; }
  .summary-stat-value { font-size: 2.2rem; }
  .def-item { margin-bottom: 8px; padding: 5px 0; }
  .example-item { padding: 8px 16px; margin-bottom: 8px; }
}

/* --- Large desktop (min 1100px) --- */
@media (min-width: 1100px) {
  :root {
    --card-max-w: 640px;
    --front-font: 3.5rem;
    --front-pad: 72px 60px;
    --back-pad: 36px 44px;
    --back-word-font: 2.3rem;
    --container-max-w: 740px;
    --container-pad: 0 36px;
  }
}

/* --- iOS safe-area for notch / home-bar --- */
@supports (padding-bottom: env(safe-area-inset-bottom)) {
  .controls {
    padding-bottom: calc(12px + env(safe-area-inset-bottom));
  }
  .app-container {
    padding-top: env(safe-area-inset-top);
  }
}