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

:root {
  --ns-yellow: #FFD417;
  --ns-blue: #003082;
  --ns-blue-light: #0067C0;
  --ns-gray: #F0F4F8;
  --ns-border: #D0D9E8;
  --correct: #00875A;
  --wrong: #C0392B;
  --text: #1A1A2E;
  --text-muted: #5C6B80;
}

body {
  font-family: 'Frutiger', 'Source Sans 3', 'Frutiger LT', 'Frutiger Neue', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--ns-gray);
  color: var(--text);
  min-height: 100vh;
}

/* Header */
.header {
  background: var(--ns-blue);
  color: white;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  height: 56px;
  gap: 1rem;
}
.header-logo {
  background: var(--ns-yellow);
  color: var(--ns-blue);
  font-weight: 900;
  font-size: 1.1rem;
  padding: 0.25rem 0.6rem;
  border-radius: 4px;
  letter-spacing: -0.5px;
  flex-shrink: 0;
}
.header-title {
  font-size: 1rem;
  font-weight: 600;
  opacity: 0.9;
}
.header-spacer { flex: 1; }
.header-link {
  color: rgba(255,255,255,0.75);
  text-decoration: none;
  font-size: 0.875rem;
}
.header-link:hover { color: white; }

/* Main layout */
.main {
  max-width: 720px;
  margin: 0 auto;
  padding: 2rem 1rem;
}

/* Cards */
.card {
  background: white;
  border-radius: 12px;
  padding: 2rem;
  box-shadow: 0 1px 3px rgba(0,0,0,0.08), 0 4px 16px rgba(0,48,130,0.06);
}

/* Landing page */
.hero {
  text-align: center;
  margin-bottom: 2rem;
}
.hero h1 {
  font-size: 2rem;
  font-weight: 800;
  color: var(--ns-blue);
  margin-bottom: 0.5rem;
}
.hero p {
  color: var(--text-muted);
  font-size: 1.05rem;
}

.form-group {
  margin-bottom: 1.25rem;
}
.form-group label {
  display: block;
  font-weight: 600;
  margin-bottom: 0.4rem;
  font-size: 0.9rem;
  color: var(--ns-blue);
}
.form-group input {
  width: 100%;
  padding: 0.75rem 1rem;
  border: 2px solid var(--ns-border);
  border-radius: 8px;
  font-size: 1rem;
  transition: border-color 0.15s;
  outline: none;
}
.form-group input:focus {
  border-color: var(--ns-blue-light);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  transition: transform 0.1s, box-shadow 0.1s, opacity 0.15s;
  text-decoration: none;
}
.btn:active { transform: scale(0.98); }
.btn-primary {
  background: var(--ns-yellow);
  color: var(--ns-blue);
  box-shadow: 0 2px 8px rgba(255,212,23,0.4);
}
.btn-primary:hover { box-shadow: 0 4px 12px rgba(255,212,23,0.5); }
.btn-secondary {
  background: var(--ns-blue);
  color: white;
}
.btn-secondary:hover { background: var(--ns-blue-light); }
.btn-outline {
  background: white;
  color: var(--ns-blue);
  border: 2px solid var(--ns-blue);
}
.btn-outline:hover { background: var(--ns-gray); }
.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
  transform: none;
}
.btn-full { width: 100%; }

/* Progress */
.progress-bar {
  height: 6px;
  background: var(--ns-border);
  border-radius: 3px;
  margin-bottom: 1.5rem;
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  background: var(--ns-yellow);
  border-radius: 3px;
  transition: width 0.3s ease;
}
.progress-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
  font-weight: 600;
  letter-spacing: 0.5px;
  text-transform: uppercase;
}

/* Sound player */
.sound-section {
  text-align: center;
  padding: 2rem 0;
  border-bottom: 1px solid var(--ns-border);
  margin-bottom: 1.5rem;
}
.sound-section h2 {
  font-size: 1.1rem;
  color: var(--text-muted);
  font-weight: 500;
  margin-bottom: 1.25rem;
}
.play-btn {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  background: var(--ns-blue);
  color: white;
  border: none;
  cursor: pointer;
  font-size: 2rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s, transform 0.1s, box-shadow 0.15s;
  box-shadow: 0 4px 16px rgba(0,48,130,0.3);
}
.play-btn:hover {
  background: var(--ns-blue-light);
  box-shadow: 0 6px 20px rgba(0,48,130,0.4);
}
.play-btn:active { transform: scale(0.95); }
.play-btn.playing {
  background: var(--ns-yellow);
  color: var(--ns-blue);
  animation: pulse 1.5s ease-in-out infinite;
}
@keyframes pulse {
  0%, 100% { box-shadow: 0 4px 16px rgba(255,212,23,0.4); }
  50% { box-shadow: 0 4px 24px rgba(255,212,23,0.7); }
}
.play-hint {
  margin-top: 0.75rem;
  font-size: 0.8rem;
  color: var(--text-muted);
}
.audio-error {
  color: var(--wrong);
  font-size: 0.85rem;
  margin-top: 0.5rem;
}

/* Train grid */
.trains-label {
  font-size: 0.85rem;
  color: var(--text-muted);
  font-weight: 600;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  margin-bottom: 0.75rem;
}
.train-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 0.75rem;
  margin-bottom: 1.5rem;
}
.train-card {
  border: 2px solid var(--ns-border);
  border-radius: 10px;
  padding: 0.75rem;
  cursor: pointer;
  text-align: center;
  transition: border-color 0.15s, background 0.15s, transform 0.1s;
  user-select: none;
  background: white;
}
.train-card:hover {
  border-color: var(--ns-blue-light);
  background: #F0F6FF;
}
.train-card.selected {
  border-color: var(--ns-blue);
  background: #EBF1FF;
  box-shadow: 0 0 0 3px rgba(0,48,130,0.12);
}
.train-card:active { transform: scale(0.97); }
.train-card img {
  width: 100%;
  height: 80px;
  object-fit: contain;
  margin-bottom: 0.5rem;
  border-radius: 4px;
}
.train-card .train-name {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--ns-blue);
}

/* Navigation row */
.nav-row {
  display: flex;
  justify-content: flex-end;
}

/* Results */
.results-header {
  text-align: center;
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--ns-border);
}
.score-badge {
  display: inline-block;
  font-size: 3rem;
  font-weight: 900;
  color: var(--ns-blue);
  line-height: 1;
}
.score-total {
  font-size: 1rem;
  color: var(--text-muted);
  margin-top: 0.25rem;
}
.rank-badge {
  display: inline-block;
  background: var(--ns-yellow);
  color: var(--ns-blue);
  font-weight: 800;
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
  font-size: 0.9rem;
  margin-top: 0.75rem;
}

.result-list { list-style: none; }
.result-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--ns-border);
  font-size: 0.9rem;
}
.result-item:last-child { border-bottom: none; }
.result-icon {
  font-size: 1.2rem;
  flex-shrink: 0;
  width: 28px;
  text-align: center;
}
.result-correct { color: var(--correct); }
.result-wrong { color: var(--wrong); }
.result-text { flex: 1; line-height: 1.4; }
.result-train-name { font-weight: 600; }
.result-your-answer { color: var(--wrong); font-size: 0.8rem; }

.result-play-btn {
  flex-shrink: 0;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  border: none;
  background: var(--ns-blue);
  color: white;
  font-size: 0.75rem;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s, transform 0.1s;
}
.result-play-btn:hover { background: var(--ns-blue-light); }
.result-play-btn:active { transform: scale(0.93); }
.result-play-btn.playing {
  background: var(--ns-yellow);
  color: var(--ns-blue);
}

.results-actions {
  display: flex;
  gap: 0.75rem;
  margin-top: 1.5rem;
  flex-wrap: wrap;
}
.results-actions .btn { flex: 1; min-width: 140px; }

/* Leaderboard */
.leaderboard-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 1rem;
}
.leaderboard-table th {
  text-align: left;
  padding: 0.5rem 0.75rem;
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-muted);
  border-bottom: 2px solid var(--ns-border);
}
.leaderboard-table td {
  padding: 0.75rem;
  border-bottom: 1px solid var(--ns-border);
  font-size: 0.9rem;
}
.leaderboard-table tr:last-child td { border-bottom: none; }
.leaderboard-table tr:hover td { background: var(--ns-gray); }
.rank-col { font-weight: 800; color: var(--ns-blue); width: 40px; }
.rank-medal { font-size: 1.1rem; }
.score-bar-wrap { display: flex; align-items: center; gap: 0.5rem; }
.score-bar {
  flex: 1;
  height: 6px;
  background: var(--ns-border);
  border-radius: 3px;
  overflow: hidden;
}
.score-bar-fill {
  height: 100%;
  background: var(--ns-yellow);
  border-radius: 3px;
}
.score-text { font-weight: 700; font-size: 0.85rem; white-space: nowrap; }
.time-col { color: var(--text-muted); font-size: 0.82rem; white-space: nowrap; }

.empty-state {
  text-align: center;
  color: var(--text-muted);
  padding: 3rem 1rem;
  font-size: 0.95rem;
}

/* Loading spinner */
.spinner {
  width: 40px;
  height: 40px;
  border: 3px solid var(--ns-border);
  border-top-color: var(--ns-blue);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin: 2rem auto;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* Utilities */
.text-center { text-align: center; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }

@media (max-width: 480px) {
  .main { padding: 1rem 0.75rem; }
  .card { padding: 1.25rem; }
  .hero h1 { font-size: 1.5rem; }
  .train-grid { grid-template-columns: repeat(2, 1fr); }
}