/* ─── Design Tokens ─────────────────────────────────────────────────────────── */
:root {
  --bg:           #080810;
  --bg-card:      #10101e;
  --bg-input:     #080810;
  --border:       #1e1e36;
  --border-focus: #5b21b6;
  --text:         #e2e8f0;
  --text-muted:   #4a5568;
  --text-dim:     #2d3748;

  --purple:       #7c3aed;
  --purple-light: #a78bfa;
  --purple-glow:  rgba(124, 58, 237, 0.35);
  --cyan:         #06b6d4;
  --cyan-glow:    rgba(6, 182, 212, 0.25);
  --red:          #ef4444;
  --blue:         #2563eb;

  --chord-maj-border: #7c3aed;
  --chord-maj-hover:  rgba(124, 58, 237, 0.18);
  --chord-min-border: #2563eb;
  --chord-min-hover:  rgba(37, 99, 235, 0.18);
  --chord-dim-border: #b91c1c;
  --chord-dim-hover:  rgba(185, 28, 28, 0.18);

  --radius-sm: 6px;
  --radius:    10px;
  --radius-lg: 14px;
}

/* ─── Reset / Base ──────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  font-size: 14px;
  line-height: 1.5;
  min-height: 100vh;
}

button { font-family: inherit; }

/* ─── Layout ────────────────────────────────────────────────────────────────── */
.app {
  max-width: 900px;
  margin: 0 auto;
  padding: 1.5rem 1.25rem 3rem;
}

/* ─── Header ────────────────────────────────────────────────────────────────── */
.app-header {
  text-align: center;
  padding: 2.5rem 0 2rem;
  margin-bottom: 1.25rem;
  border-bottom: 1px solid var(--border);
}

.app-header h1 {
  font-size: 2.25rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  background: linear-gradient(135deg, var(--purple-light) 0%, var(--cyan) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.app-header p {
  margin-top: 0.35rem;
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* ─── Cards ─────────────────────────────────────────────────────────────────── */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  margin-bottom: 1rem;
}

.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1rem;
}

.card h2 {
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--text-muted);
}

.step-count {
  font-size: 0.7rem;
  color: var(--text-dim);
  margin-left: 0.4rem;
  font-weight: 400;
  text-transform: none;
  letter-spacing: 0;
}

/* ─── Controls Row ───────────────────────────────────────────────────────────── */
.controls-card {
  margin-bottom: 1rem;
}

.controls-row {
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem;
  align-items: flex-end;
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.control-group--wide { min-width: 160px; flex: 1; }

.control-group label {
  font-size: 0.65rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.value-badge {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--purple-light);
  font-size: 0.7rem;
  font-weight: 600;
  padding: 0 5px;
  font-variant-numeric: tabular-nums;
  min-width: 2.8rem;
  text-align: center;
  text-transform: none;
  letter-spacing: 0;
}

select {
  appearance: none;
  background: var(--bg-input) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6' viewBox='0 0 10 6'%3E%3Cpath d='M0 0l5 6 5-6z' fill='%234a5568'/%3E%3C/svg%3E") no-repeat right 10px center;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  cursor: pointer;
  font-size: 0.85rem;
  outline: none;
  padding: 0.45rem 2rem 0.45rem 0.65rem;
  transition: border-color 0.15s;
}

select:hover, select:focus { border-color: var(--border-focus); }
select option { background: #1a1a2e; }

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  background: transparent;
  cursor: pointer;
  height: 20px;
  outline: none;
  width: 100%;
}

input[type="range"]::-webkit-slider-runnable-track {
  background: var(--border);
  border-radius: 2px;
  height: 3px;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  background: var(--purple);
  border-radius: 50%;
  box-shadow: 0 0 8px var(--purple-glow);
  height: 14px;
  margin-top: -5.5px;
  width: 14px;
  transition: transform 0.1s, box-shadow 0.1s;
}

input[type="range"]:hover::-webkit-slider-thumb,
input[type="range"]:focus::-webkit-slider-thumb {
  transform: scale(1.2);
  box-shadow: 0 0 12px var(--purple-glow);
}

input[type="range"]::-moz-range-track {
  background: var(--border);
  border-radius: 2px;
  height: 3px;
}

input[type="range"]::-moz-range-thumb {
  background: var(--purple);
  border: none;
  border-radius: 50%;
  box-shadow: 0 0 8px var(--purple-glow);
  height: 14px;
  width: 14px;
}

/* ─── Preset Row ─────────────────────────────────────────────────────────────── */
.preset-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.preset-label {
  font-size: 0.65rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  white-space: nowrap;
}

.preset-row select {
  font-size: 0.78rem;
  padding-top: 0.3rem;
  padding-bottom: 0.3rem;
}

/* ─── Chord Palette ──────────────────────────────────────────────────────────── */
.chord-palette {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 0.5rem;
  margin-bottom: 0.75rem;
}

.chord-btn {
  align-items: center;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  border-top-width: 3px;
  color: var(--text);
  cursor: pointer;
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
  justify-content: center;
  min-height: 78px;
  padding: 0.65rem 0.3rem;
  transition: transform 0.12s, box-shadow 0.12s, background 0.12s;
  user-select: none;
}

.chord-btn:hover {
  transform: translateY(-3px);
}

.chord-btn:active { transform: translateY(-1px); }

.chord-btn.chord-maj { border-top-color: var(--chord-maj-border); }
.chord-btn.chord-maj:hover {
  background: var(--chord-maj-hover);
  box-shadow: 0 6px 18px var(--purple-glow);
}

.chord-btn.chord-min { border-top-color: var(--chord-min-border); }
.chord-btn.chord-min:hover {
  background: var(--chord-min-hover);
  box-shadow: 0 6px 18px rgba(37, 99, 235, 0.25);
}

.chord-btn.chord-dim { border-top-color: var(--chord-dim-border); }
.chord-btn.chord-dim:hover {
  background: var(--chord-dim-hover);
  box-shadow: 0 6px 18px rgba(185, 28, 28, 0.25);
}

.chord-numeral {
  color: var(--text-muted);
  font-size: 0.6rem;
  font-weight: 500;
  letter-spacing: 0.04em;
}

.chord-name {
  color: var(--text);
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.chord-notes {
  color: var(--text-dim);
  font-size: 0.58rem;
  letter-spacing: 0.03em;
}

.chord-legend {
  display: flex;
  gap: 1rem;
  justify-content: flex-end;
}

.legend-item {
  font-size: 0.65rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.legend-item::before {
  content: '';
  display: block;
  width: 20px;
  height: 3px;
  border-radius: 2px;
}

.legend-maj::before { background: var(--chord-maj-border); }
.legend-min::before { background: var(--chord-min-border); }
.legend-dim::before { background: var(--chord-dim-border); }

/* ─── Progression ────────────────────────────────────────────────────────────── */
.progression-steps {
  align-content: flex-start;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  min-height: 86px;
}

.empty-hint {
  align-self: center;
  color: var(--text-dim);
  font-size: 0.82rem;
  font-style: italic;
  text-align: center;
  width: 100%;
  padding: 1rem 0;
}

.step {
  align-items: center;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  cursor: default;
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
  min-width: 68px;
  padding: 0.55rem 0.65rem;
  position: relative;
  transition: border-color 0.1s, background 0.1s, box-shadow 0.1s;
}

.step.active {
  background: rgba(124, 58, 237, 0.15);
  border-color: var(--purple);
  box-shadow: 0 0 16px var(--purple-glow);
}

.step-numeral {
  color: var(--text-dim);
  font-size: 0.6rem;
  letter-spacing: 0.04em;
}

.step-name {
  color: var(--text);
  font-size: 0.9rem;
  font-weight: 700;
}

.step-notes {
  color: var(--text-dim);
  font-size: 0.58rem;
}

.step-remove {
  align-items: center;
  background: var(--red);
  border: none;
  border-radius: 50%;
  color: white;
  cursor: pointer;
  display: none;
  font-size: 0.7rem;
  height: 17px;
  justify-content: center;
  line-height: 1;
  padding-bottom: 1px;
  position: absolute;
  right: -6px;
  top: -6px;
  width: 17px;
}

.step:hover .step-remove { display: flex; }

/* ─── Synth Settings ─────────────────────────────────────────────────────────── */
.synth-settings {
  overflow: hidden;
  transition: max-height 0.25s ease;
  max-height: 500px;
}

.synth-settings.collapsed { max-height: 0; }

.settings-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 1rem;
}

/* ─── Buttons ────────────────────────────────────────────────────────────────── */
.btn-ghost {
  background: none;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-muted);
  cursor: pointer;
  font-size: 0.75rem;
  padding: 0.3rem 0.75rem;
  transition: border-color 0.15s, color 0.15s;
}

.btn-ghost:hover { border-color: var(--text-muted); color: var(--text); }
.btn-danger:hover { border-color: var(--red) !important; color: var(--red) !important; }

.toggle-btn {
  font-size: 0.65rem;
  padding: 0.25rem 0.6rem;
}

/* ─── Waveform + Playback ────────────────────────────────────────────────────── */
.playback-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

#waveform {
  display: block;
  width: 100%;
  height: 64px;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
}

.playback-controls {
  display: flex;
  gap: 0.75rem;
  justify-content: center;
  padding: 1.1rem;
}

.btn-play,
.btn-stop {
  border: none;
  border-radius: 50px;
  cursor: pointer;
  font-size: 0.9rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  padding: 0.7rem 2.25rem;
  transition: transform 0.15s, box-shadow 0.15s, opacity 0.15s;
}

.btn-play {
  background: linear-gradient(135deg, #6d28d9, #4f46e5);
  box-shadow: 0 4px 16px var(--purple-glow);
  color: #fff;
}

.btn-play:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px var(--purple-glow);
}

.btn-play:disabled { opacity: 0.45; cursor: not-allowed; }

.btn-stop {
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--text);
}

.btn-stop:hover:not(:disabled) {
  border-color: var(--red);
  color: var(--red);
}

.btn-stop:disabled { opacity: 0.35; cursor: not-allowed; }

/* ─── Responsive ─────────────────────────────────────────────────────────────── */
@media (max-width: 640px) {
  .chord-palette {
    grid-template-columns: repeat(4, 1fr);
  }

  .controls-row {
    gap: 0.9rem;
  }

  .app-header h1 { font-size: 1.75rem; }
}

@media (max-width: 480px) {
  .chord-palette {
    grid-template-columns: repeat(3, 1fr);
  }
}