/* ============ VocabMaster Design System ============ */
:root {
  --bg-primary: #0f1923;
  --bg-secondary: #1a2a3a;
  --bg-elevated: #243447;
  --border: #2a3a5a;
  --border-light: #3a4a6a;
  --text-primary: #e8edf3;
  --text-secondary: #b0bec5;
  --text-muted: #6c7a89;
  --accent: #4fc3f7;
  --accent-hover: #29b6f6;
  --accent-dim: rgba(79, 195, 247, 0.15);
  --success: #4caf50;
  --warning: #ff9800;
  --danger: #e74c3c;
  --gold: #ffc107;
  --purple: #9c27b0;
  --shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html, body { height: 100%; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", Roboto, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
  font-size: 17px;
  line-height: 1.6;
}

#app { min-height: 100vh; display: flex; flex-direction: column; max-width: 920px; margin: 0 auto; }

/* ============ Top Bar ============ */
.top-bar {
  display: flex; justify-content: space-between; align-items: center;
  padding: 16px 24px;
  background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
  border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 100;
}
.logo { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 18px; }
.logo-icon { font-size: 24px; }
.top-stats { display: flex; gap: 12px; }
.stat-pill {
  display: flex; align-items: center; gap: 6px;
  padding: 6px 12px;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 20px;
  font-size: 13px;
  color: var(--text-secondary);
}
.stat-icon { font-size: 14px; }

/* ============ Main Views ============ */
main { flex: 1; padding: 24px; padding-bottom: 100px; }
.view { display: none; animation: fadeIn 0.3s ease; }
.view.active { display: block; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }

.hero { text-align: center; padding: 36px 16px; margin-bottom: 28px; }
.hero h1 {
  font-size: 48px;
  font-weight: 800;
  letter-spacing: -1px;
  background: linear-gradient(135deg, #4fc3f7, #9c27b0);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 12px;
}
.hero-sub { color: var(--text-secondary); font-size: 17px; }

/* ============ Level Grid ============ */
.level-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(170px, 1fr));
  gap: 12px;
  margin-bottom: 32px;
}
.level-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 18px;
  cursor: pointer;
  transition: all 0.2s;
  position: relative;
  overflow: hidden;
  border-left: 4px solid var(--level-color, var(--accent));
}
.level-card:hover {
  border-color: var(--level-color, var(--accent));
  transform: translateY(-3px);
  box-shadow: var(--shadow);
}
.level-card.selected { border-color: var(--level-color, var(--accent)); background: var(--accent-dim); }
.level-card .level-icon { font-size: 32px; margin-bottom: 8px; }
.level-card .level-name { font-size: 19px; font-weight: 700; margin-bottom: 4px; }
.level-card .level-name-en { font-size: 12px; color: var(--text-muted); margin-bottom: 10px; text-transform: uppercase; letter-spacing: 0.5px; }
.level-card .level-count { font-size: 28px; font-weight: 800; color: var(--level-color, var(--accent)); }
.level-card .level-count-label { font-size: 13px; color: var(--text-muted); }
.level-card .level-progress {
  position: absolute; bottom: 0; left: 0; right: 0; height: 4px;
  background: var(--bg-elevated);
}
.level-card .level-progress-fill { height: 100%; background: var(--accent); transition: width 0.3s; }

/* Browse-level (词海漫游) - distinct visual treatment */
.level-card.browse {
  background: linear-gradient(135deg, rgba(0, 188, 212, 0.15), rgba(79, 195, 247, 0.1));
  border-left: 4px solid #00bcd4;
  border-style: dashed;
}
.level-card.browse .level-icon { font-size: 36px; }
.level-card.browse .level-count { color: #00bcd4; }

/* ============ Browse View ============ */
.browse-search-row {
  display: flex; gap: 10px; margin-bottom: 12px;
}
.browse-search-row input {
  flex: 1;
  padding: 10px 14px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text-primary);
  font-size: 14px;
  font-family: inherit;
}
.browse-search-row input:focus { outline: none; border-color: var(--accent); }
.browse-word-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 20px;
  margin-bottom: 16px;
  min-height: 200px;
}
.browse-word-row {
  display: flex; align-items: center; gap: 10px;
  margin-bottom: 12px; flex-wrap: wrap;
}
.browse-word { font-size: 42px; font-weight: 800; letter-spacing: 1.5px; }

/* ============ Quick Actions ============ */
.quick-actions {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 12px;
  margin-top: 16px;
}
.action-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 18px;
  text-align: left;
  cursor: pointer;
  transition: all 0.2s;
  color: inherit;
  font-family: inherit;
}
.action-card:hover { border-color: var(--accent); transform: translateY(-2px); }
.action-icon { font-size: 24px; margin-bottom: 8px; }
.action-title { font-size: 15px; font-weight: 600; margin-bottom: 4px; }
.action-desc { font-size: 12px; color: var(--text-muted); }

/* ============ Setup View ============ */
.back-btn {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-secondary);
  padding: 8px 14px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 13px;
  margin-bottom: 16px;
  font-family: inherit;
}
.back-btn:hover { border-color: var(--accent); color: var(--accent); }

h2 { font-size: 30px; margin-bottom: 18px; font-weight: 800; }
.muted { color: var(--text-muted); margin-bottom: 16px; }

.setup-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 22px;
  margin-bottom: 18px;
}
.setup-card h3 { font-size: 18px; margin-bottom: 14px; color: var(--text-secondary); font-weight: 700; }

.setup-summary { padding: 12px; background: var(--bg-elevated); border-radius: 10px; margin-bottom: 12px; }
.setup-summary .ss-name { font-size: 18px; font-weight: 600; }
.setup-summary .ss-desc { font-size: 12px; color: var(--text-muted); }

.path-display {
  padding: 14px;
  background: linear-gradient(135deg, rgba(79, 195, 247, 0.1), rgba(156, 39, 176, 0.1));
  border: 1px solid var(--accent-dim);
  border-radius: 10px;
}
.path-display .path-title { font-size: 13px; color: var(--accent); margin-bottom: 8px; font-weight: 600; }
.path-display .path-stats { display: flex; gap: 16px; flex-wrap: wrap; }
.path-display .path-stat { font-size: 12px; }
.path-display .path-stat strong { color: var(--text-primary); font-size: 16px; display: block; }
.path-display .path-bar { height: 8px; background: var(--bg-elevated); border-radius: 4px; overflow: hidden; margin-top: 8px; }
.path-display .path-bar-fill { height: 100%; background: linear-gradient(90deg, var(--accent), var(--purple)); transition: width 0.5s; }

.mode-options { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 10px; }
.mode-option {
  display: flex; gap: 12px;
  padding: 12px;
  background: var(--bg-elevated);
  border: 2px solid transparent;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.2s;
}
.mode-option:has(input:checked) { border-color: var(--accent); background: var(--accent-dim); }
.mode-option input { display: none; }
.mode-icon { font-size: 22px; }
.mode-name { font-size: 14px; font-weight: 600; }
.mode-desc { font-size: 11px; color: var(--text-muted); margin-top: 2px; }

.setting-row {
  display: flex; align-items: center; justify-content: space-between;
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
  font-size: 14px;
  flex-wrap: wrap;
  gap: 12px;
}
.setting-row:last-child { border-bottom: none; }
.setting-row label { font-weight: 500; }
.setting-row select, .setting-row input[type="number"], .setting-row input[type="text"] {
  padding: 6px 12px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text-primary);
  font-size: 13px;
  font-family: inherit;
}

.checkbox-group { display: flex; gap: 14px; flex-wrap: wrap; }
.checkbox-group label { display: flex; align-items: center; gap: 4px; font-size: 13px; cursor: pointer; }

/* Toggle switch */
.switch { position: relative; display: inline-block; width: 44px; height: 24px; }
.switch input { opacity: 0; width: 0; height: 0; }
.slider {
  position: absolute; cursor: pointer;
  top: 0; left: 0; right: 0; bottom: 0;
  background: var(--border);
  transition: 0.3s;
  border-radius: 24px;
}
.slider:before {
  position: absolute; content: "";
  height: 18px; width: 18px;
  left: 3px; bottom: 3px;
  background: white;
  transition: 0.3s;
  border-radius: 50%;
}
input:checked + .slider { background: var(--accent); }
input:checked + .slider:before { transform: translateX(20px); }

/* ============ Buttons ============ */
.primary-btn {
  width: 100%;
  padding: 16px;
  background: linear-gradient(135deg, var(--accent), var(--purple));
  border: none;
  border-radius: 12px;
  color: white;
  font-size: 17px;
  font-weight: 700;
  cursor: pointer;
  margin-top: 16px;
  font-family: inherit;
  transition: transform 0.1s, box-shadow 0.2s;
}
.primary-btn:hover { transform: translateY(-2px); box-shadow: 0 6px 20px rgba(79, 195, 247, 0.3); }
.primary-btn:active { transform: translateY(0); }
.primary-btn:disabled { opacity: 0.5; cursor: not-allowed; transform: none; }

.secondary-btn {
  padding: 12px 20px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 10px;
  color: var(--text-primary);
  font-size: 14px;
  cursor: pointer;
  font-family: inherit;
  transition: all 0.2s;
}
.secondary-btn:hover { border-color: var(--accent); color: var(--accent); }

/* ============ Quiz View ============ */
.quiz-header {
  display: flex; align-items: center; gap: 16px;
  margin-bottom: 24px;
  padding: 12px 16px;
  background: var(--bg-secondary);
  border-radius: 12px;
}
.quiz-progress { font-size: 14px; font-weight: 600; min-width: 50px; }
.quiz-progress-bar { flex: 1; height: 6px; background: var(--bg-elevated); border-radius: 3px; overflow: hidden; }
.quiz-progress-fill { height: 100%; background: linear-gradient(90deg, var(--accent), var(--success)); transition: width 0.3s; width: 10%; }
.quit-btn {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-muted);
  padding: 6px 12px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 12px;
  font-family: inherit;
}
.quit-btn:hover { color: var(--danger); border-color: var(--danger); }

.quiz-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 32px 24px;
  text-align: center;
  min-height: 280px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}
.q-mode-tag {
  display: inline-block;
  padding: 6px 16px;
  background: var(--accent-dim);
  color: var(--accent);
  border-radius: 14px;
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 18px;
}
.q-zh-meaning {
  font-size: 36px;
  font-weight: 700;
  color: var(--gold);
  margin: 8px 0 18px;
  letter-spacing: 1px;
  line-height: 1.4;
}
.q-word { font-size: 56px; font-weight: 800; margin-bottom: 16px; letter-spacing: 2px; }
.q-pronunciation { display: flex; gap: 12px; margin-bottom: 24px; }
.q-pronunciation span { color: var(--text-muted); font-size: 17px; font-style: italic; }
.q-sentence { font-size: 21px; line-height: 1.7; margin-bottom: 24px; max-width: 600px; }
.q-sentence .blank { display: inline-block; min-width: 100px; border-bottom: 2px dashed var(--accent); padding: 0 8px; color: transparent; }
.q-sentence .blank.reveal { color: var(--success); border-bottom-color: var(--success); }

.q-options { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; width: 100%; max-width: 560px; }
.q-option {
  padding: 18px 20px;
  background: var(--bg-elevated);
  border: 2px solid var(--border);
  border-radius: 12px;
  cursor: pointer;
  font-size: 19px;
  font-weight: 500;
  text-align: left;
  color: var(--text-primary);
  font-family: inherit;
  transition: all 0.2s;
}
.q-option:hover { border-color: var(--accent); }
.q-option.correct { border-color: var(--success); background: rgba(76, 175, 80, 0.15); color: var(--success); }
.q-option.wrong { border-color: var(--danger); background: rgba(231, 76, 60, 0.15); color: var(--danger); }
.q-option.disabled { cursor: not-allowed; opacity: 0.7; }
.q-option .opt-letter { display: inline-block; width: 28px; height: 28px; line-height: 28px; text-align: center; background: var(--bg-primary); border-radius: 50%; margin-right: 10px; font-size: 14px; font-weight: 700; }

.q-spell-input {
  width: 100%;
  max-width: 480px;
  padding: 18px;
  background: var(--bg-elevated);
  border: 2px solid var(--border);
  border-radius: 12px;
  color: var(--text-primary);
  font-size: 32px;
  font-weight: 600;
  text-align: center;
  letter-spacing: 4px;
  font-family: inherit;
}
.q-spell-input:focus { outline: none; border-color: var(--accent); }
.q-spell-hint { margin-top: 14px; color: var(--text-muted); font-size: 16px; }

.q-actions { margin-top: 24px; display: flex; gap: 12px; justify-content: center; }

/* Quiz Feedback */
.quiz-feedback { margin-top: 16px; }
.feedback-card {
  padding: 20px;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 14px;
  margin-bottom: 10px;
}
.feedback-card.correct { border-color: var(--success); }
.feedback-card.wrong { border-color: var(--danger); }
.feedback-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 12px; }
.feedback-status { font-weight: 700; font-size: 17px; }
.feedback-card.correct .feedback-status { color: var(--success); }
.feedback-card.wrong .feedback-status { color: var(--danger); }
.feedback-word { font-size: 36px; font-weight: 800; letter-spacing: 1px; }
.feedback-zh {
  display: inline-block;
  margin-left: 12px;
  font-size: 22px;
  color: var(--gold);
  font-weight: 600;
}
.feedback-def { color: var(--text-secondary); font-size: 16px; margin: 10px 0 14px; padding: 10px 14px; background: var(--bg-elevated); border-radius: 10px; line-height: 1.7; }
.feedback-def strong { color: var(--accent); margin-right: 4px; }
.ex-en { color: var(--text-primary); font-size: 19px; line-height: 1.7; margin-bottom: 8px; font-weight: 500; }
.ex-zh { color: var(--text-muted); font-size: 15px; line-height: 1.7; font-style: italic; padding-left: 14px; border-left: 3px solid var(--accent-dim); }
.next-btn { width: 100%; padding: 16px; font-size: 17px; }
.example-tabs { display: flex; gap: 8px; margin-bottom: 12px; }
.example-tab {
  padding: 6px 14px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-muted);
}
.example-tab.active { background: var(--accent-dim); color: var(--accent); border-color: var(--accent); }
.example-content { padding: 14px; background: var(--bg-elevated); border-radius: 10px; font-size: 16px; line-height: 1.7; }
.example-content .src { display: block; color: var(--text-muted); font-size: 11px; margin-top: 4px; font-style: italic; }
.tts-btn {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--accent);
  padding: 4px 8px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 12px;
  font-family: inherit;
}

/* ============ Results View ============ */
.results-hero { text-align: center; padding: 32px 16px; }
.score-circle {
  width: 140px; height: 140px;
  margin: 0 auto 24px;
  border-radius: 50%;
  background: conic-gradient(var(--accent) 0deg, var(--bg-elevated) 0deg);
  display: flex; flex-direction: column;
  align-items: center; justify-content: center;
  position: relative;
}
.score-circle::before {
  content: ""; position: absolute; inset: 8px;
  border-radius: 50%; background: var(--bg-primary);
}
.score-value { font-size: 36px; font-weight: 700; color: var(--accent); position: relative; z-index: 1; }
.score-label { font-size: 11px; color: var(--text-muted); position: relative; z-index: 1; }

.results-stats { display: flex; gap: 12px; justify-content: center; margin: 20px 0; flex-wrap: wrap; }
.result-stat {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px 20px;
  min-width: 80px;
}
.result-stat-num { font-size: 22px; font-weight: 700; color: var(--accent); }
.result-stat-label { font-size: 11px; color: var(--text-muted); }

.results-actions { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; margin: 24px 0; }
.results-actions .primary-btn,
.results-actions .secondary-btn { width: auto; min-width: 140px; margin: 0; }

.word-review { margin-top: 24px; }
.word-review h3 { font-size: 16px; margin-bottom: 12px; color: var(--text-secondary); }
.review-item {
  display: flex; justify-content: space-between; align-items: center;
  padding: 12px;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 8px;
  margin-bottom: 8px;
}
.review-item .word { font-weight: 600; }
.review-item .status { font-size: 12px; }
.review-item .status.correct { color: var(--success); }
.review-item .status.wrong { color: var(--danger); }

/* ============ Customize / Templates ============ */
.template-list { list-style: none; margin-bottom: 16px; }
.template-item {
  display: flex; justify-content: space-between; align-items: center;
  padding: 12px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 8px;
  margin-bottom: 8px;
}
.template-item .tpl-name { font-weight: 600; }
.template-item .tpl-meta { font-size: 11px; color: var(--text-muted); }
.template-item-actions { display: flex; gap: 6px; }
.template-item button {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-muted);
  padding: 4px 8px;
  border-radius: 4px;
  cursor: pointer;
  font-size: 11px;
  font-family: inherit;
}
.template-item button:hover { color: var(--accent); border-color: var(--accent); }
.template-item button.delete:hover { color: var(--danger); border-color: var(--danger); }

.template-actions { display: flex; gap: 10px; margin-top: 16px; }

/* ============ Progress View ============ */
#progress-content .level-progress-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px;
  margin-bottom: 12px;
}
.level-progress-card .lp-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 10px; }
.level-progress-card .lp-name { font-weight: 600; font-size: 16px; }
.level-progress-card .lp-pct { color: var(--accent); font-weight: 700; }
.level-progress-card .lp-bar { height: 8px; background: var(--bg-elevated); border-radius: 4px; overflow: hidden; }
.level-progress-card .lp-bar-fill { height: 100%; background: linear-gradient(90deg, var(--accent), var(--success)); }

/* ============ Bottom Nav ============ */
.bottom-nav {
  position: fixed; bottom: 0; left: 0; right: 0;
  max-width: 920px; margin: 0 auto;
  display: flex;
  background: rgba(15, 25, 35, 0.95);
  backdrop-filter: blur(12px);
  border-top: 1px solid var(--border);
  z-index: 100;
}
.nav-btn {
  flex: 1;
  background: transparent;
  border: none;
  padding: 12px;
  cursor: pointer;
  color: var(--text-muted);
  display: flex; flex-direction: column; align-items: center; gap: 4px;
  font-family: inherit;
  font-size: 11px;
  transition: color 0.2s;
}
.nav-btn.active { color: var(--accent); }
.nav-icon { font-size: 20px; }

/* ============ Responsive ============ */
@media (max-width: 600px) {
  body { font-size: 15px; }
  .top-bar { padding: 12px 16px; }
  .logo-text { display: none; }
  .top-stats { gap: 6px; }
  .stat-pill { padding: 4px 8px; font-size: 11px; }
  main { padding: 16px; padding-bottom: 100px; }
  .hero h1 { font-size: 32px; }
  .hero-sub { font-size: 14px; }
  .q-word { font-size: 42px; }
  .feedback-word { font-size: 28px; }
  .ex-en { font-size: 17px; }
  .q-option { font-size: 17px; padding: 14px 16px; }
  .q-options { grid-template-columns: 1fr; }
  .level-grid { grid-template-columns: repeat(auto-fill, minmax(140px, 1fr)); }
  .level-card .level-count { font-size: 22px; }
}

/* ============ Animations ============ */
@keyframes slideUp { from { transform: translateY(20px); opacity: 0; } to { transform: translateY(0); opacity: 1; } }
.slide-up { animation: slideUp 0.4s ease; }
@keyframes pulse { 0%, 100% { opacity: 1; } 50% { opacity: 0.5; } }
.loading { animation: pulse 1.5s infinite; }