:root {
  --bg: #0f0f1a;
  --card-bg: #1a1a2e;
  --card-hover: #222244;
  --text: #e4e4f0;
  --text-dim: #8888aa;
  --primary: #7c6ff2;
  --primary-light: #a78bfa;
  --accent: #f59e0b;
  --green: #34d399;
  --red: #f87171;
  --border: #2a2a44;
  --radius: 12px;
  --radius-sm: 8px;
  --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
}

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

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-tap-highlight-color: transparent;
  -webkit-font-smoothing: antialiased;
}

.container { max-width: 720px; margin: 0 auto; padding: 16px; }

header { text-align: center; padding: 24px 0 16px; }
header h1 { font-size: 28px; font-weight: 700; color: #fff; }
.subtitle { color: var(--text-dim); font-size: 14px; margin-top: 2px; }

.nav-bar { display: flex; gap: 8px; justify-content: center; margin-top: 16px; }
.nav-link {
  padding: 8px 20px; border-radius: 20px; font-size: 14px;
  text-decoration: none; color: var(--text-dim); transition: all .2s;
  background: var(--card-bg); border: 1px solid var(--border);
}
.nav-link.active { background: var(--primary); color: #fff; border-color: var(--primary); }
.nav-link:hover { background: var(--card-hover); }

.user-bar {
  display: flex; align-items: center; justify-content: center; gap: 8px;
  margin-top: 12px; flex-wrap: wrap; font-size: 13px; color: var(--text-dim);
}
.user-bar select, .user-bar input {
  padding: 6px 10px; border-radius: var(--radius-sm); border: 1px solid var(--border);
  background: #111128; color: #fff; font-size: 13px; font-family: var(--font); outline: none;
}
.user-bar select:focus, .user-bar input:focus { border-color: var(--primary); }
.user-bar input { width: 120px; }
.current-user-tag {
  background: var(--primary); color: #fff; padding: 2px 12px;
  border-radius: 10px; font-size: 13px; font-weight: 600;
}

.sentence-list { display: flex; flex-direction: column; gap: 12px; margin-top: 16px; }

.sentence-card {
  display: block; background: var(--card-bg); border-radius: var(--radius);
  padding: 16px; text-decoration: none; color: inherit;
  border: 1px solid var(--border); transition: all .2s; cursor: pointer;
}
.sentence-card:hover { background: var(--card-hover); border-color: var(--primary); transform: translateY(-1px); }
.sentence-card:active { transform: scale(0.98); }

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

.sentence-id { font-size: 12px; color: var(--text-dim); font-weight: 600; }
.sentence-source { font-size: 11px; color: var(--primary-light); }

.card-english { font-size: 16px; font-weight: 500; color: #fff; margin-bottom: 6px; line-height: 1.5; }
.card-chinese { font-size: 14px; color: var(--text-dim); }

.card-source { font-size: 11px; color: var(--primary-light); margin-top: 6px; }

.star { color: #333355; font-size: 14px; transition: color .2s; }
.star.filled { color: var(--accent); }

.sentence-detail { margin-top: 16px; }
.detail-header { display: flex; gap: 12px; align-items: center; margin-bottom: 20px; }
.sentence-source { font-size: 12px; color: var(--primary-light); background: rgba(124, 111, 242, 0.1); padding: 2px 10px; border-radius: 10px; }

.english-sentence {
  font-size: 22px; font-weight: 600; line-height: 1.6; color: #fff;
  padding: 20px; background: var(--card-bg); border-radius: var(--radius);
  border: 1px solid var(--border); margin-bottom: 12px;
}
.english-sentence .word { cursor: pointer; display: inline-block; padding: 0 1px; transition: all .15s; border-radius: 4px; }
.english-sentence .word:hover { background: rgba(124, 111, 242, 0.2); color: var(--primary-light); }
.english-sentence .word:active { background: rgba(124, 111, 242, 0.4); }
.word-punct { color: var(--text-dim); }
.word-blank { color: var(--accent); font-weight: 700; }

.chinese-translation {
  font-size: 16px; color: var(--text-dim); padding: 12px 20px;
  background: var(--card-bg); border-radius: var(--radius); border: 1px solid var(--border);
  margin-bottom: 16px;
}

.action-buttons { display: flex; gap: 10px; margin-bottom: 16px; }

.btn {
  padding: 12px 24px; border: none; border-radius: var(--radius-sm); font-size: 15px;
  font-weight: 600; cursor: pointer; transition: all .2s; font-family: var(--font);
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  min-height: 44px; user-select: none;
}
.btn:active { transform: scale(0.96); }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-light); }
.btn-secondary { background: var(--card-bg); color: var(--text); border: 1px solid var(--border); }
.btn-secondary:hover { background: var(--card-hover); border-color: var(--primary); }
.btn-sm { padding: 6px 16px; font-size: 13px; min-height: 32px; }
.btn-nav { background: var(--card-bg); color: var(--text); text-decoration: none; border: 1px solid var(--border); flex: 1; }
.btn-nav:hover { border-color: var(--primary); }

.cloze-section {
  background: var(--card-bg); border-radius: var(--radius); padding: 16px;
  border: 1px solid var(--primary); margin-bottom: 16px;
}
.cloze-sentence { font-size: 18px; line-height: 1.6; color: #fff; margin-bottom: 12px; }
.cloze-input-group { display: flex; gap: 8px; }
.cloze-input-group input {
  flex: 1; padding: 10px 14px; border: 1px solid var(--border); border-radius: var(--radius-sm);
  background: #111128; color: #fff; font-size: 16px; font-family: var(--font); outline: none;
}
.cloze-input-group input:focus { border-color: var(--primary); }
.cloze-result { margin-top: 10px; font-size: 15px; font-weight: 600; }
.cloze-result.correct { color: var(--green); }
.cloze-result.incorrect { color: var(--red); }

.word-result {
  background: var(--card-bg); border-radius: var(--radius); padding: 16px;
  border: 1px solid var(--accent); margin-bottom: 16px;
  animation: fadeIn .2s ease;
}
.word-result-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 8px; }
.word-result-header span { font-size: 20px; font-weight: 700; color: var(--accent); }
.word-result-def { font-size: 15px; color: var(--text-dim); line-height: 1.5; }
.btn-close { background: none; border: none; color: var(--text-dim); font-size: 18px; cursor: pointer; padding: 4px 8px; }

.familiarity-section {
  display: flex; align-items: center; gap: 10px; padding: 12px 0;
  margin-bottom: 16px;
}
.fam-label { font-size: 14px; color: var(--text-dim); }
.fam-stars { display: flex; gap: 4px; }
.fam-stars .star { font-size: 28px; cursor: pointer; transition: all .15s; }
.fam-stars .star:hover { transform: scale(1.2); }

.nav-buttons { display: flex; gap: 10px; margin-bottom: 24px; }

.hidden { display: none !important; }

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

.stats-summary { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; margin-bottom: 16px; }
.stat-card {
  background: var(--card-bg); border-radius: var(--radius); padding: 16px;
  text-align: center; border: 1px solid var(--border);
}
.stat-value { font-size: 28px; font-weight: 700; color: var(--primary-light); }
.stat-label { font-size: 12px; color: var(--text-dim); margin-top: 4px; }

.filter-bar { display: flex; gap: 8px; margin-bottom: 12px; }
.filter-bar .btn { border: 1px solid var(--border); background: var(--card-bg); color: var(--text-dim); }
.filter-bar .btn.active { background: var(--primary); color: #fff; border-color: var(--primary); }

.progress-list { display: flex; flex-direction: column; gap: 10px; }
.progress-card {
  display: block; background: var(--card-bg); border-radius: var(--radius); padding: 14px;
  text-decoration: none; color: inherit; border: 1px solid var(--border);
  transition: all .2s; cursor: pointer;
}
.progress-card:hover { border-color: var(--primary); }
.progress-meta { display: flex; gap: 16px; font-size: 12px; color: var(--text-dim); margin-top: 8px; }

.empty-state { text-align: center; color: var(--text-dim); padding: 40px 0; font-size: 15px; }

@media (max-width: 480px) {
  .container { padding: 12px; }
  .english-sentence { font-size: 18px; padding: 14px; }
  .action-buttons { flex-direction: column; }
  .stats-summary { grid-template-columns: repeat(3, 1fr); gap: 6px; }
  .stat-card { padding: 12px 8px; }
  .stat-value { font-size: 22px; }
}

/* Recording section */
.btn-recording {
  background: #10b981;
  color: #fff;
  border: none;
  padding: 12px 24px;
  border-radius: var(--radius-sm);
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  transition: all .2s;
  font-family: var(--font);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  min-height: 44px;
  user-select: none;
}
.btn-recording:hover { background: #34d399; }
.btn-recording:active { transform: scale(0.96); }
.btn-recording:disabled { opacity: 0.5; cursor: not-allowed; }

.recording-section {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 16px;
  border: 1px solid #10b981;
  margin-bottom: 16px;
  animation: fadeIn .2s ease;
}

.recording-status {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--text-dim);
  margin-bottom: 12px;
}

.recording-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #555;
  display: inline-block;
}
.recording-dot.active {
  background: #f87171;
  animation: pulse 1s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.3; }
}

.recording-timer {
  font-size: 32px;
  font-weight: 700;
  color: #fff;
  text-align: center;
  padding: 16px 0;
  font-variant-numeric: tabular-nums;
}

.recording-controls {
  display: flex;
  gap: 10px;
  justify-content: center;
  flex-wrap: wrap;
}

.recording-result {
  margin-top: 16px;
  padding: 16px;
  background: rgba(16, 185, 129, 0.05);
  border-radius: var(--radius-sm);
  text-align: center;
}

.result-detail {
  margin-top: 12px;
  font-size: 14px;
  color: var(--text-dim);
  line-height: 1.6;
}

.result-history {
  margin-top: 16px;
  text-align: left;
}

.history-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-dim);
  margin-bottom: 8px;
  padding-bottom: 6px;
  border-bottom: 1px solid var(--border);
}

.history-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 8px 0;
  border-bottom: 1px solid rgba(42, 42, 68, 0.5);
  font-size: 13px;
}

.history-score {
  font-weight: 700;
  min-width: 60px;
}

.history-grade {
  color: var(--text-dim);
  min-width: 40px;
}

.history-time {
  color: var(--text-dim);
  font-size: 12px;
  margin-left: auto;
}
.recording-badge { font-size: 12px; color: #10b981; font-weight: 600; }