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

:root {
  --bg: #0d1b2a;
  --surface: #1b2838;
  --surface2: #243447;
  --primary: #00d4ff;
  --success: #00e676;
  --error: #ff5252;
  --warn: #ffab40;
  --text: #e0e0e0;
  --text-dim: #8899aa;
  --radius: 12px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  overflow-x: hidden;
}

/* Header */
.header {
  background: var(--surface);
  padding: 16px 20px;
  text-align: center;
  border-bottom: 2px solid var(--primary);
}
.header h1 { font-size: 1.3rem; color: var(--primary); }
.header p { font-size: 0.8rem; color: var(--text-dim); margin-top: 4px; }

/* Tabs */
.tabs {
  display: flex;
  background: var(--surface);
  border-bottom: 1px solid var(--surface2);
}
.tab {
  flex: 1;
  padding: 14px 8px;
  text-align: center;
  cursor: pointer;
  font-size: 0.9rem;
  color: var(--text-dim);
  border-bottom: 3px solid transparent;
  transition: all 0.2s;
}
.tab.active {
  color: var(--primary);
  border-bottom-color: var(--primary);
  background: var(--surface2);
}

/* Content */
.content { padding: 20px; max-width: 600px; margin: 0 auto; }
.panel { display: none; }
.panel.active { display: block; }

/* Cards */
.card {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 16px;
}

/* Word display */
.word-display {
  text-align: center;
  padding: 30px 20px;
}
.word-en {
  font-size: 2.2rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: 8px;
}
.word-ko {
  font-size: 1.1rem;
  color: var(--primary);
}
.word-counter {
  font-size: 0.8rem;
  color: var(--text-dim);
  margin-top: 12px;
}

/* Buttons */
.btn-row {
  display: flex;
  gap: 10px;
  margin-top: 16px;
}
.btn {
  flex: 1;
  padding: 14px 12px;
  border: none;
  border-radius: var(--radius);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}
.btn:active { transform: scale(0.96); }
.btn-listen { background: var(--surface2); color: var(--primary); }
.btn-record { background: var(--error); color: #fff; }
.btn-record.recording { background: #ff1744; animation: pulse 1s infinite; }
.btn-shadow { background: #7c4dff; color: #fff; }
.btn-next { background: var(--surface2); color: var(--text); }
.btn-prev { background: var(--surface2); color: var(--text); }
.btn-small { padding: 10px 16px; font-size: 0.85rem; }
.btn-success { background: var(--success); color: #000; }

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.7; }
}

/* Result */
.result-area {
  margin-top: 16px;
  padding: 16px;
  border-radius: var(--radius);
  background: var(--surface2);
  text-align: center;
  display: none;
}
.result-area.show { display: block; }
.result-score {
  font-size: 2rem;
  font-weight: 700;
}
.result-score.good { color: var(--success); }
.result-score.bad { color: var(--error); }
.result-score.mid { color: var(--warn); }
.result-text {
  margin-top: 8px;
  font-size: 0.9rem;
  color: var(--text-dim);
}
.result-recognized {
  margin-top: 12px;
  font-size: 1rem;
  color: var(--text);
  font-style: italic;
}

/* Sentence highlight */
.sentence-result {
  margin-top: 16px;
  line-height: 2;
  font-size: 1.2rem;
}
.word-correct { color: var(--success); font-weight: 600; }
.word-wrong { color: var(--error); text-decoration: underline; font-weight: 600; }

/* Visualizer */
.viz-container {
  margin-top: 16px;
}
.viz-label {
  font-size: 0.75rem;
  color: var(--text-dim);
  margin-bottom: 4px;
  text-transform: uppercase;
  letter-spacing: 1px;
}
canvas.waveform {
  width: 100%;
  height: 80px;
  background: var(--surface2);
  border-radius: 8px;
  margin-bottom: 12px;
}

/* Shadow mode */
.shadow-status {
  text-align: center;
  padding: 20px;
  font-size: 1rem;
  color: var(--text-dim);
}
.shadow-status.active { color: var(--primary); }

/* Nav arrows */
.nav-row {
  display: flex;
  gap: 10px;
  margin-top: 12px;
}

/* Browser warning */
.warning {
  background: rgba(255, 171, 64, 0.15);
  border: 1px solid var(--warn);
  border-radius: var(--radius);
  padding: 14px;
  margin-bottom: 16px;
  font-size: 0.85rem;
  color: var(--warn);
  text-align: center;
}

/* Loading */
.loading {
  display: inline-block;
  width: 20px; height: 20px;
  border: 2px solid var(--text-dim);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* Mobile */
@media (max-width: 480px) {
  .header { padding: 4px 8px !important; border-bottom-width: 1px !important; }
  .header h1 { font-size: .88rem !important; line-height: 1.05 !important; }
  .header p { display: none !important; }
  .tabs { gap: 2px !important; margin: 2px 4px 5px !important; position: sticky; top: 0; z-index: 5; }
  .tab { padding: 5px 3px !important; font-size: .7rem !important; border-bottom-width: 2px !important; }
  .content { padding: 5px; }
  .card { padding: 10px; margin-bottom: 6px; }
  #assignment-banner { padding: 7px 8px !important; margin-bottom: 6px !important; border-radius: 10px !important; }
  #assignment-title { font-size: .76rem !important; line-height: 1.1 !important; }
  #assignment-meta { font-size: .64rem !important; margin-top: 2px !important; line-height: 1.2 !important; }
  #assignment-progress { font-size: .68rem !important; margin-top: 4px !important; line-height: 1.1 !important; }
  #assignment-progress-fill { min-height: 5px !important; }
  #assignment-banner > div[style*='height:8px'] { height: 5px !important; margin-top: 4px !important; }
  #assignment-banner button { margin-top: 6px !important; padding: 7px 8px !important; font-size: .76rem !important; border-radius: 10px !important; }
  #assignment-submit-note { font-size: .6rem !important; margin-top: 4px !important; line-height: 1.15 !important; }
  .word-display { padding: 11px 8px; }
  .word-en { font-size: 1.34rem; margin-bottom: 3px; line-height: 1.16; }
  .word-ko { font-size: .88rem; }
  .word-counter { margin-top: 4px; font-size: .68rem; }
  .viz-container { margin-top: 6px; }
  .viz-label { font-size: .6rem; margin-bottom: 2px; }
  canvas.waveform { height: 42px; margin-bottom: 5px; }
  .btn-row { gap: 6px; margin-top: 6px; }
  .btn { padding: 8px 7px; font-size: 0.8rem; gap: 5px; }
  .btn-small { padding: 6px 8px; font-size: 0.72rem; }
  .nav-row { gap: 6px; margin-top: 6px; }
  .result-area { margin-top: 6px; padding: 7px; }
  .result-score { font-size: 1.05rem; line-height: 1.05; }
  .result-text, .result-recognized { margin-top: 3px; font-size: .72rem; line-height: 1.2; }
  .sentence-result { margin-top: 6px; line-height: 1.35; font-size: .82rem; }
}

@media (max-width: 390px) {
  .header { padding: 4px 8px !important; }
  .header h1 { font-size: .86rem !important; }
  .tabs { margin: 3px 5px 5px !important; }
  .tab { padding: 5px 3px !important; font-size: .68rem !important; }
  .content { padding: 5px; }
  .card { padding: 9px; }
  #assignment-banner { padding: 6px !important; }
  #assignment-title { font-size: .72rem !important; }
  #assignment-meta, #assignment-progress, #assignment-submit-note { font-size: .58rem !important; }
  .word-display { padding: 10px 8px; }
  .word-en { font-size: 1.28rem; }
  .word-ko { font-size: .84rem; }
  canvas.waveform { height: 40px; margin-bottom: 5px; }
  .btn { padding: 8px 6px; font-size: 0.78rem; }
  .btn-small { padding: 6px 8px; font-size: 0.7rem; }
  .result-area { padding: 7px; }
  .result-score { font-size: 1.06rem; }
  .result-text, .result-recognized { font-size: .72rem; }
}