:root {
  --bg: #0e0e0e;
  --surface: #1a1a1a;
  --surface2: #242424;
  --border: #333;
  --accent: #f5c842;
  --accent2: #e8453c;
  --green: #4caf7d;
  --text: #f0ede6;
  --muted: #888;
  --correct: #4caf7d;
  --wrong: #e8453c;
}

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

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'IBM Plex Sans', sans-serif;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 24px 16px 60px;
}

/* Noise overlay */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.04'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: 999;
  opacity: 0.4;
}

/* ─── Back Link ──────────────────────────────────────────────────────────── */

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--muted);
  text-decoration: none;
  margin-bottom: 20px;
  transition: color 0.15s;
}

.back-link:hover { color: var(--accent); }

/* ─── Header ─────────────────────────────────────────────────────────────── */

header {
  width: 100%;
  max-width: 700px;
  margin-bottom: 32px;
  text-align: center;
}

.logo {
  font-family: 'Bebas Neue', sans-serif;
  font-size: clamp(42px, 8vw, 72px);
  letter-spacing: 3px;
  line-height: 1;
  color: var(--accent);
  text-shadow: 4px 4px 0 #8a6e00;
}

.subtitle {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px;
  letter-spacing: 4px;
  text-transform: uppercase;
  color: var(--muted);
  margin-top: 6px;
}

/* ─── Score Bar ──────────────────────────────────────────────────────────── */

.scorebar {
  display: flex;
  gap: 20px;
  justify-content: center;
  margin-top: 18px;
  flex-wrap: wrap;
}

.score-pill {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 8px 20px;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.score-pill .val {
  font-size: 20px;
  font-weight: 600;
  color: var(--accent);
}

.score-pill.streak .val { color: var(--green); }

/* ─── Settings Panel ─────────────────────────────────────────────────────── */

.settings {
  width: 100%;
  max-width: 700px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 20px 24px;
  margin-bottom: 24px;
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
  align-items: flex-end;
}

.setting-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
  flex: 1;
  min-width: 140px;
}

.setting-group label {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10px;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--muted);
}

.setting-group select,
.setting-group input[type="range"] {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text);
  font-family: 'IBM Plex Mono', monospace;
  font-size: 13px;
  padding: 8px 12px;
  width: 100%;
  outline: none;
  cursor: pointer;
}

.setting-group select:focus {
  border-color: var(--accent);
}

.checkbox-row {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.key-toggle {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 6px 12px;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px;
  cursor: pointer;
  transition: all 0.15s;
  user-select: none;
  color: #fff;
}

.key-toggle.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #000;
  font-weight: 600;
}

/* ─── Quiz Card ──────────────────────────────────────────────────────────── */

.quiz-card {
  width: 100%;
  max-width: 700px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 36px 32px;
  position: relative;
  overflow: hidden;
  transition: border-color 0.3s;
}

.quiz-card.correct { border-color: var(--correct); }
.quiz-card.wrong   { border-color: var(--wrong); }

.quiz-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: var(--accent);
  transition: background 0.3s;
}

.quiz-card.correct::before { background: var(--correct); }
.quiz-card.wrong::before   { background: var(--wrong); }

.question-meta {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10px;
  letter-spacing: 3px;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 20px;
  display: flex;
  justify-content: space-between;
}

.question-type { color: var(--accent); }

.question-text {
  font-size: clamp(15px, 3vw, 17px);
  line-height: 1.6;
  color: var(--muted);
  margin-bottom: 8px;
  font-weight: 300;
}

.question-main {
  font-family: 'Bebas Neue', sans-serif;
  font-size: clamp(36px, 7vw, 56px);
  letter-spacing: 2px;
  line-height: 1;
  color: var(--text);
  margin-bottom: 8px;
}

.question-main .numbers   { color: var(--accent); }

.question-main .key-badge {
  display: inline-block;
  background: var(--accent2);
  color: #fff;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.45em;
  font-weight: 600;
  letter-spacing: 1px;
  padding: 4px 10px;
  border-radius: 3px;
  vertical-align: middle;
  margin-left: 10px;
  position: relative;
  top: -4px;
}

/* ─── Answer Area ────────────────────────────────────────────────────────── */

.answer-area { margin-top: 28px; }

/* Multiple choice */
.choices-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
}

@media (max-width: 480px) {
  .choices-grid { grid-template-columns: 1fr; }
}

.choice-btn {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 5px;
  color: var(--text);
  font-family: 'IBM Plex Mono', monospace;
  font-size: 15px;
  font-weight: 600;
  padding: 16px;
  cursor: pointer;
  transition: all 0.15s;
  text-align: left;
  display: flex;
  align-items: center;
  gap: 10px;
  letter-spacing: 1px;
}

.choice-btn:hover:not(:disabled) {
  border-color: var(--accent);
  background: #242200;
  transform: translateY(-1px);
}

.choice-btn.correct {
  background: #0d2b1a;
  border-color: var(--correct);
  color: var(--correct);
}

.choice-btn.wrong {
  background: #2b0d0d;
  border-color: var(--wrong);
  color: var(--wrong);
}

.choice-btn .choice-letter {
  background: var(--border);
  border-radius: 3px;
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
  flex-shrink: 0;
}

.choice-btn.correct .choice-letter { background: var(--correct); color: #000; }
.choice-btn.wrong .choice-letter   { background: var(--wrong);   color: #fff; }

/* Type-in */
.type-input-row {
  display: flex;
  gap: 10px;
  align-items: stretch;
}

.type-input {
  flex: 1;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 5px;
  color: var(--text);
  font-family: 'IBM Plex Mono', monospace;
  font-size: 20px;
  font-weight: 600;
  padding: 14px 18px;
  outline: none;
  transition: border-color 0.2s;
  letter-spacing: 2px;
}

.type-input:focus   { border-color: var(--accent); }
.type-input.correct { border-color: var(--correct); background: #0d2b1a; color: var(--correct); }
.type-input.wrong   { border-color: var(--wrong);   background: #2b0d0d; color: var(--wrong); }

.submit-btn {
  background: var(--accent);
  border: none;
  border-radius: 5px;
  color: #000;
  font-family: 'Bebas Neue', sans-serif;
  font-size: 18px;
  letter-spacing: 2px;
  padding: 0 24px;
  cursor: pointer;
  transition: all 0.15s;
}

.submit-btn:hover  { background: #ffd700; transform: translateY(-1px); }
.submit-btn:active { transform: translateY(0); }

/* ─── Symbol Toolbar ─────────────────────────────────────────────────────── */

.symbol-toolbar {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 12px;
  align-items: center;
}

.symbol-toolbar-label {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10px;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--muted);
  margin-right: 2px;
}

.sym-btn {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text);
  font-family: 'IBM Plex Mono', monospace;
  font-size: 15px;
  font-weight: 600;
  width: 42px;
  height: 42px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.12s;
  position: relative;
  flex-shrink: 0;
}

.sym-btn:hover {
  background: var(--accent);
  border-color: var(--accent);
  color: #000;
  transform: translateY(-2px);
  box-shadow: 0 4px 10px rgba(245, 200, 66, 0.25);
}

.sym-btn:active { transform: translateY(0); }

.sym-btn .sym-tooltip {
  position: absolute;
  bottom: calc(100% + 6px);
  left: 50%;
  transform: translateX(-50%);
  background: #000;
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 10px;
  letter-spacing: 1px;
  white-space: nowrap;
  padding: 4px 8px;
  border-radius: 3px;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.15s;
}

.sym-btn:hover .sym-tooltip { opacity: 1; }

.sym-btn.sym-highlight {
  border-color: var(--accent);
  color: var(--accent);
}

/* ─── Feedback ───────────────────────────────────────────────────────────── */

.feedback {
  margin-top: 20px;
  padding: 16px 18px;
  border-radius: 5px;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 13px;
  display: none;
  line-height: 1.7;
}

.feedback.show    { display: block; }
.feedback.correct { background: #0d2b1a; border: 1px solid var(--correct); color: var(--correct); }
.feedback.wrong   { background: #2b0d0d; border: 1px solid var(--wrong);   color: var(--wrong); }

.feedback .correct-answer {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 4px;
}

.feedback .explanation {
  color: var(--muted);
  font-size: 11px;
  margin-top: 6px;
}

/* ─── Next Button ────────────────────────────────────────────────────────── */

.next-btn {
  display: none;
  margin-top: 20px;
  width: 100%;
  background: transparent;
  border: 1px solid var(--accent);
  border-radius: 5px;
  color: var(--accent);
  font-family: 'Bebas Neue', sans-serif;
  font-size: 20px;
  letter-spacing: 3px;
  padding: 14px;
  cursor: pointer;
  transition: all 0.15s;
}

.next-btn:hover  { background: var(--accent); color: #000; }
.next-btn.show   { display: block; }

/* ─── Hint Row ───────────────────────────────────────────────────────────── */

.hint-row {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px;
  color: var(--muted);
  margin-top: 10px;
  letter-spacing: 1px;
}

/* ─── Reference Chart ────────────────────────────────────────────────────── */

.ref-toggle {
  width: 100%;
  max-width: 700px;
  margin-top: 20px;
  background: transparent;
  border: 1px dashed var(--border);
  border-radius: 5px;
  color: var(--muted);
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px;
  letter-spacing: 2px;
  text-transform: uppercase;
  padding: 10px;
  cursor: pointer;
  transition: all 0.15s;
}

.ref-toggle:hover { border-color: var(--accent); color: var(--accent); }

.ref-table-wrap {
  width: 100%;
  max-width: 700px;
  display: none;
  margin-top: 10px;
  /* Allow horizontal scroll on mobile instead of overflowing */
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.ref-table-wrap.show { display: block; }

.ref-table {
  width: 100%;
  min-width: 520px; /* prevents columns from collapsing too small */
  border-collapse: collapse;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px;
}

.ref-table th {
  background: var(--surface);
  border: 1px solid var(--border);
  padding: 8px 6px;
  text-align: center;
  color: var(--accent);
  font-weight: 600;
  letter-spacing: 1px;
  white-space: nowrap;
}

.ref-table td {
  background: var(--surface);
  border: 1px solid var(--border);
  padding: 6px 4px;
  text-align: center;
  color: var(--text);
  white-space: nowrap;
}

.ref-table tr:hover td { background: var(--surface2); }

.ref-table .row-key {
  color: var(--accent);
  font-weight: 600;
  padding: 6px 8px;
}

/* Chord cell layout */
.ref-chord-name {
  display: block;
  margin-bottom: 3px;
  font-size: 11px;
}

.ref-btn-group {
  display: flex;
  gap: 3px;
  justify-content: center;
}

.ref-play-btn {
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 3px;
  color: var(--muted);
  font-size: 10px;
  padding: 2px 4px;
  cursor: pointer;
  transition: all 0.15s;
  line-height: 1.4;
}

.ref-play-btn:hover {
  background: var(--accent);
  border-color: var(--accent);
  color: #000;
}

.ref-play-btn.playing {
  background: var(--green);
  border-color: var(--green);
  color: #000;
}

.ref-piano-btn {
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 3px;
  color: var(--muted);
  font-size: 10px;
  padding: 2px 4px;
  cursor: pointer;
  transition: all 0.15s;
  line-height: 1.4;
}

.ref-piano-btn:hover {
  background: var(--surface2);
  border-color: var(--accent);
  color: var(--accent);
}

.ref-piano-btn.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #000;
}

/* Mobile scroll hint */
.ref-scroll-hint {
  display: none;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10px;
  letter-spacing: 1px;
  color: var(--muted);
  text-align: center;
  padding: 6px 0 2px;
}

@media (max-width: 600px) {
  .ref-scroll-hint { display: block; }

  .ref-table {
    font-size: 11px;
  }

  .ref-table th {
    padding: 6px 4px;
    font-size: 10px;
    letter-spacing: 0;
  }

  .ref-table td {
    padding: 5px 3px;
  }

  .ref-chord-name {
    font-size: 10px;
  }

  .ref-play-btn,
  .ref-piano-btn {
    font-size: 9px;
    padding: 1px 3px;
  }
}

/* ─── Chord Panel ─────────────────────────────────────────────────────────── */

.chord-panel-row td {
  background: #111 !important;
  padding: 0 !important;
  border-top: none !important;
}

.chord-panel {
  padding: 16px 20px 20px;
  border-bottom: 1px solid var(--border);
  animation: slideDown 0.2s ease;
}

@keyframes slideDown {
  from { opacity: 0; transform: translateY(-6px); }
  to   { opacity: 1; transform: translateY(0); }
}

.chord-panel-header {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 14px;
}

.chord-panel-title {
  font-family: 'Bebas Neue', sans-serif;
  font-size: 28px;
  letter-spacing: 2px;
  color: var(--accent);
  line-height: 1;
}

.chord-panel-notes {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px;
  color: var(--muted);
  letter-spacing: 2px;
}

.chord-panel-close {
  margin-left: auto;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 3px;
  color: var(--muted);
  font-size: 11px;
  padding: 2px 8px;
  cursor: pointer;
  transition: all 0.15s;
}

.chord-panel-close:hover {
  border-color: var(--wrong);
  color: var(--wrong);
}

.chord-panel-keyboard {
  overflow-x: auto;
  padding-bottom: 4px;
}

.piano-svg {
  display: block;
  width: 100%;
  max-width: 520px;
  height: auto;
  min-width: 280px;
}

/* ─── Progress Bar ───────────────────────────────────────────────────────── */

.progress-wrap {
  width: 100%;
  max-width: 700px;
  height: 3px;
  background: var(--surface);
  border-radius: 2px;
  margin-bottom: 16px;
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  background: var(--accent);
  border-radius: 2px;
  transition: width 0.4s ease;
}

/* ─── Mode Tabs ──────────────────────────────────────────────────────────── */

.mode-tabs {
  display: flex;
  gap: 0;
  width: 100%;
  max-width: 700px;
  margin-bottom: 16px;
}

.mode-tab {
  flex: 1;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--muted);
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10px;
  letter-spacing: 2px;
  text-transform: uppercase;
  padding: 9px 6px;
  cursor: pointer;
  transition: all 0.15s;
  text-align: center;
}

.mode-tab:first-child  { border-radius: 5px 0 0 5px; }
.mode-tab:last-child   { border-radius: 0 5px 5px 0; border-left: none; }
.mode-tab:not(:first-child):not(:last-child) { border-left: none; }

.mode-tab.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #000;
  font-weight: 600;
}

/* ─── Animations ─────────────────────────────────────────────────────────── */

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  20%       { transform: translateX(-8px); }
  40%       { transform: translateX(8px); }
  60%       { transform: translateX(-5px); }
  80%       { transform: translateX(5px); }
}

@keyframes pop {
  0%   { transform: scale(1); }
  50%  { transform: scale(1.03); }
  100% { transform: scale(1); }
}

.shake { animation: shake 0.35s ease; }
.pop   { animation: pop   0.25s ease; }

/* ─── Pitch Trainer Link ──────────────────────────────────────────────────── */

.pitch-trainer-link {
  width: 100%;
  max-width: 700px;
  margin-top: 16px;
  display: flex;
  align-items: center;
  gap: 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 18px 24px;
  text-decoration: none;
  color: var(--text);
  transition: all 0.2s;
}

.pitch-trainer-link:hover {
  border-color: var(--accent);
  background: var(--surface2);
  transform: translateY(-2px);
  box-shadow: 0 4px 20px rgba(245,200,66,0.1);
}

.pitch-trainer-link-icon {
  font-size: 28px;
  flex-shrink: 0;
}

.pitch-trainer-link-title {
  font-family: 'Bebas Neue', sans-serif;
  font-size: 22px;
  letter-spacing: 2px;
  color: var(--accent);
}

.pitch-trainer-link-sub {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px;
  letter-spacing: 1px;
  color: var(--muted);
  margin-top: 2px;
}

.pitch-trainer-link-arrow {
  margin-left: auto;
  font-size: 20px;
  color: var(--accent);
  flex-shrink: 0;
  transition: transform 0.2s;
}

.pitch-trainer-link:hover .pitch-trainer-link-arrow {
  transform: translateX(4px);
}