/* ===== CSS Custom Properties ===== */

:root {
  /* Light theme palette */
  --bg-page: #f4f5f7;
  --bg-card: #ffffff;
  --bg-inset: #eef0f4;
  --bg-pill: #edf0f5;
  --bg-pill-hover: #e2e6ed;

  --border: #dce0e8;
  --border-light: #e8ecf1;

  --text: #1a1d23;
  --text-secondary: #4a5060;
  --text-muted: #7c8496;
  --text-label: #5a6170;
  --text-dim: #9aa2b1;

  /* Accent palette (brand teal) */
  --accent: #4a9fa1;
  --accent-soft: #ecf7f7;
  --accent-text: #357678;

  --green: #16a34a;
  --green-soft: #ecfdf3;
  --green-text: #15803d;
  --amber: #d97706;
  --amber-soft: #fffbeb;
  --red: #dc2626;
  --red-soft: #fef2f2;

  /* Section accent colors */
  --notation-accent: #4a9fa1;
  --notation-soft: #ecf7f7;
  --hud-accent: #16a34a;
  --hud-soft: #ecfdf3;
  --tone-accent: #c9a23e;
  --tone-soft: #fdf8ec;
  --vis-accent: #e67e22;
  --vis-soft: #fff8f0;
  --settings-accent: #64748b;

  /* Spacing */
  --gap-xs: 0.25rem;
  --gap-sm: 0.5rem;
  --gap-md: 0.75rem;
  --gap-lg: 1rem;

  /* Radii */
  --r-sm: 0.5rem;
  --r-md: 0.625rem;
  --r-lg: 0.875rem;
  --r-pill: 999px;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.07), 0 1px 3px rgba(0,0,0,0.05);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.1), 0 2px 6px rgba(0,0,0,0.04);

  font-family: Inter, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.5;
  color: var(--text);
  background-color: var(--bg-page);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg-page);
}

/* ===== Unified Pill Button System ===== */

.pill-group {
  display: flex;
  border-radius: var(--r-pill);
  overflow: hidden;
  background: var(--bg-pill);
  padding: 2px;
  gap: 2px;
}

.pill-btn {
  border: 0;
  background: transparent;
  color: var(--text-muted);
  padding: 0.35rem 0.75rem;
  font-size: 0.88rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 150ms;
  white-space: nowrap;
  border-radius: var(--r-pill);
}

.pill-btn + .pill-btn {
  border-left: none;
}

.pill-btn.active {
  background: var(--bg-card);
  color: var(--accent-text);
  box-shadow: var(--shadow-sm);
}

.pill-btn:hover:not(.active) {
  background: var(--bg-pill-hover);
  color: var(--text-secondary);
}

/* ===== Card Component ===== */

.card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--r-lg);
  padding: var(--gap-md) var(--gap-lg);
  box-shadow: var(--shadow-sm);
  transition: box-shadow 250ms, transform 250ms;
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  border-radius: var(--r-lg) var(--r-lg) 0 0;
}

.card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-1px);
}

.card-title {
  margin: 0 0 var(--gap-sm);
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-dim);
}

/* Card accent colors via top border */
.notation-card::before { background: var(--notation-accent); }
.singing-hud::before   { background: var(--hud-accent); }
.tone-card::before     { background: var(--tone-accent); }
.vis-card::before      { background: var(--vis-accent); }
.settings-card::before { background: var(--settings-accent); }

/* ===== Header Bar ===== */

.header-bar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: 0.55rem 1rem;
  box-shadow: 0 1px 4px rgba(0,0,0,0.04);
}

.header-inner {
  max-width: 64rem;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: var(--gap-md);
  flex-wrap: wrap;
}

.header-title {
  margin: 0;
  font-size: 1.2rem;
  font-weight: 800;
  white-space: nowrap;
  background: linear-gradient(135deg, #4a9fa1, #357678);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.header-logo {
  height: 1.6rem;
  width: auto;
  flex-shrink: 0;
}

.header-docs-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.4rem;
  height: 1.4rem;
  border-radius: 50%;
  background: var(--bg-inset);
  border: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.8rem;
  font-weight: 700;
  text-decoration: none;
  line-height: 1;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
  flex-shrink: 0;
}
.header-docs-link:hover {
  background: var(--accent-soft);
  color: var(--accent-text);
  border-color: var(--accent);
}

.header-group {
  display: flex;
  align-items: center;
  gap: var(--gap-sm);
  flex-wrap: wrap;
}

.header-group label {
  font-weight: 600;
  color: var(--text-muted);
  font-size: 0.9rem;
  white-space: nowrap;
}

.header-group select {
  border: 1px solid var(--border);
  border-radius: var(--r-sm);
  background: var(--bg-card);
  color: var(--text);
  padding: 0.3rem 0.5rem;
  font-size: 0.9rem;
  cursor: pointer;
  transition: border-color 150ms;
}

.header-group select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 2px var(--accent-soft);
}

.header-sep {
  width: 1px;
  height: 1.4rem;
  background: var(--border);
  flex-shrink: 0;
}

#mode-toggle-group {
  flex-shrink: 0;
}

.header-signout {
  margin-left: auto;
  border: 1px solid var(--border);
  border-radius: var(--r-pill);
  background: var(--bg-inset);
  color: var(--text-muted);
  font-size: 0.82rem;
  font-weight: 600;
  padding: 0.22rem 0.6rem;
  cursor: pointer;
  white-space: nowrap;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
  flex-shrink: 0;
}
.header-signout:hover {
  background: var(--red-soft);
  color: var(--red);
  border-color: var(--red);
}

.ref-freq {
  color: var(--text-muted);
  font-size: 0.9rem;
  font-variant-numeric: tabular-nums;
  font-weight: 500;
}

/* ===== Target Info Bar ===== */

.target-bar {
  max-width: 64rem;
  margin: 0 auto;
  padding: 0.4rem 1rem;
}

.target-info {
  margin: 0;
  color: var(--accent-text);
  font-size: 0.95rem;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  text-align: center;
  background: var(--accent-soft);
  padding: 0.35rem 0.75rem;
  border-radius: var(--r-sm);
  border: 1px solid rgba(79, 109, 245, 0.12);
}

/* ===== Main Layout ===== */

.main-layout {
  max-width: 64rem;
  margin: 0 auto;
  padding: 0.6rem 0.75rem 2rem;
  display: flex;
  flex-direction: column;
  gap: var(--gap-md);
}

/* ===== Notation Card (staff + keyboard) ===== */

.notation-card .visual-displays {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--gap-xs);
  width: 100%;
}

.staff-canvas {
  width: 100%;
  height: 7rem;
  border-radius: var(--r-sm);
  border: 1px solid var(--border);
}

.keyboard-canvas {
  width: 100%;
  height: 4rem;
  border-radius: var(--r-sm);
  border: 1px solid var(--border);
}

/* ===== Singing HUD Card ===== */

.singing-hud {
  text-align: center;
  transition: border-color 400ms, box-shadow 400ms;
}

.singing-hud.in-tune {
  border-color: var(--green);
  box-shadow: 0 0 0 3px var(--green-soft), var(--shadow-md);
}

.mic-btn {
  border: 0;
  border-radius: var(--r-pill);
  padding: 0.65rem 1.5rem;
  font-size: 0.95rem;
  font-weight: 700;
  background: linear-gradient(135deg, #22c55e, #16a34a);
  color: #fff;
  cursor: pointer;
  transition: all 200ms;
  width: 100%;
  max-width: 16rem;
  box-shadow: 0 2px 8px rgba(22,163,74,0.25);
  letter-spacing: 0.01em;
}

.mic-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 14px rgba(22,163,74,0.35);
}

.mic-btn.active {
  background: linear-gradient(135deg, #ef4444, #dc2626);
  box-shadow: 0 2px 8px rgba(220,38,38,0.3);
}

.mic-btn.active:hover {
  box-shadow: 0 4px 14px rgba(220,38,38,0.4);
}

.mic-status-text {
  margin: 0.35rem 0 0;
  font-size: 0.82rem;
  color: var(--text-dim);
  font-weight: 500;
}

/* Pitch readout (inside HUD) */

.pitch-display {
  display: none;
  flex-direction: column;
  align-items: center;
  gap: 0.15rem;
  margin-top: var(--gap-sm);
}

.pitch-display.visible {
  display: flex;
}

.detected-note {
  margin: 0;
  font-size: clamp(2rem, 7vw, 3.2rem);
  font-weight: 800;
  letter-spacing: 0.02em;
  line-height: 1.1;
  color: var(--text);
}

.detected-freq {
  margin: 0;
  color: var(--text-muted);
  font-size: 0.9rem;
  font-variant-numeric: tabular-nums;
}

.cents-row {
  display: flex;
  align-items: baseline;
  gap: var(--gap-sm);
  margin-top: 0.1rem;
}

.cents-label {
  color: var(--text-muted);
  font-size: 0.9rem;
}

.cents-offset {
  font-size: 1.4rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  transition: color 150ms ease;
}

/* Cents gauge bar */

.cents-gauge {
  position: relative;
  width: 100%;
  max-width: 16rem;
  height: 0.55rem;
  background: var(--bg-inset);
  border-radius: var(--r-pill);
  margin: 0.4rem auto 0;
  overflow: visible;
  border: 1px solid var(--border-light);
}

.cents-gauge-center {
  position: absolute;
  top: -2px;
  left: 50%;
  transform: translateX(-50%);
  width: 2px;
  height: calc(100% + 4px);
  background: var(--text-dim);
  border-radius: 1px;
}

.cents-gauge-needle {
  position: absolute;
  top: 50%;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  transform: translate(-50%, -50%);
  left: 50%;
  background: var(--green);
  transition: left 80ms linear, background-color 150ms;
  box-shadow: 0 0 6px currentColor, 0 1px 3px rgba(0,0,0,0.2);
  border: 2px solid var(--bg-card);
}

/* Input meter (compact, inside HUD) */

.meter {
  width: 100%;
  max-width: 16rem;
  height: 0.35rem;
  border-radius: var(--r-pill);
  background: var(--bg-inset);
  overflow: hidden;
  margin: 0.4rem auto 0;
}

.meter-fill {
  width: 0%;
  height: 100%;
  background: linear-gradient(90deg, var(--red) 0%, var(--amber) 45%, var(--green) 100%);
  transition: width 80ms linear;
  border-radius: var(--r-pill);
}

.meter-value {
  margin: 0.15rem 0 0;
  color: var(--text-dim);
  font-size: 0.78rem;
  font-variant-numeric: tabular-nums;
  text-align: center;
}

/* ===== Tone Card ===== */

.tone-card .tone-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--gap-sm);
  flex-wrap: wrap;
  margin-top: var(--gap-sm);
}

.tone-card .tone-row label {
  font-weight: 600;
  color: var(--text-label);
  font-size: 0.9rem;
}

.tone-card .tone-row select {
  border: 1px solid var(--border);
  border-radius: var(--r-sm);
  background: var(--bg-card);
  color: var(--text);
  padding: 0.3rem 0.5rem;
  font-size: 0.9rem;
  cursor: pointer;
}

.tone-card .tone-row select:focus {
  outline: none;
  border-color: var(--tone-accent);
  box-shadow: 0 0 0 2px var(--tone-soft);
}

.tone-controls {
  display: flex;
  align-items: center;
  gap: var(--gap-sm);
  flex-wrap: wrap;
  justify-content: center;
}

.tone-btn {
  border: 2px solid var(--tone-accent);
  border-radius: var(--r-pill);
  background: var(--tone-soft);
  color: var(--tone-accent);
  padding: 0.45rem 1.1rem;
  font-size: 0.95rem;
  font-weight: 700;
  cursor: pointer;
  user-select: none;
  -webkit-user-select: none;
  touch-action: none;
  transition: all 150ms;
}

.tone-btn:hover {
  background: var(--tone-accent);
  color: #fff;
  box-shadow: 0 2px 8px rgba(139,92,246,0.3);
}

.tone-btn.playing {
  background: var(--tone-accent);
  color: #fff;
  box-shadow: 0 2px 10px rgba(139,92,246,0.4);
}

.chord-play-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--gap-sm);
  flex-wrap: wrap;
  margin-top: var(--gap-sm);
}

.chord-play-row.hidden { display: none; }

.chord-play-row label {
  font-weight: 600;
  color: var(--text-label);
  font-size: 0.88rem;
}

/* ===== Visualization Card (tabbed) ===== */

.vis-tabs {
  display: flex;
  gap: 2px;
  background: var(--bg-inset);
  border-radius: var(--r-sm);
  padding: 3px;
  margin-bottom: var(--gap-sm);
}

.vis-tab {
  border: 0;
  background: transparent;
  color: var(--text-muted);
  padding: 0.4rem 0.85rem;
  font-size: 0.88rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 150ms;
  border-radius: calc(var(--r-sm) - 2px);
  flex: 1;
  text-align: center;
}

.vis-tab.active {
  color: var(--vis-accent);
  background: var(--bg-card);
  box-shadow: var(--shadow-sm);
}

.vis-tab:hover:not(.active) {
  color: var(--text-secondary);
  background: var(--bg-pill-hover);
}

.vis-container {
  position: relative;
  width: 100%;
}

.vis-canvas {
  width: 100%;
  height: 12rem;
  border-radius: var(--r-sm);
  border: 1px solid var(--border);
  display: none;
}

.vis-canvas.active {
  display: block;
}

/* ===== Settings Card (collapsible) ===== */

.settings-card {
  overflow: hidden;
}

.settings-toggle {
  display: flex;
  align-items: center;
  gap: var(--gap-sm);
  background: transparent;
  border: 0;
  color: var(--text-muted);
  font-size: 0.82rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  cursor: pointer;
  padding: 0;
  width: 100%;
  transition: color 150ms;
}

.settings-toggle:hover {
  color: var(--text-secondary);
}

.settings-toggle .arrow {
  display: inline-block;
  transition: transform 200ms;
  font-size: 0.6rem;
}

.settings-toggle.open .arrow {
  transform: rotate(90deg);
}

.settings-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height 300ms ease, padding 300ms ease;
  padding-top: 0;
}

.settings-body.open {
  max-height: 36rem;
  padding-top: var(--gap-sm);
}

.settings-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--gap-sm);
  flex-wrap: wrap;
  padding: 0.35rem 0;
  border-bottom: 1px solid var(--border-light);
}

.settings-row:last-child {
  border-bottom: none;
}

.settings-row label {
  font-weight: 600;
  color: var(--text-label);
  font-size: 0.9rem;
  white-space: nowrap;
}

.settings-select {
  border: 1px solid var(--border);
  border-radius: var(--r-sm);
  background: var(--bg-card);
  color: var(--text);
  padding: 0.3rem 0.5rem;
  font-size: 0.85rem;
  cursor: pointer;
  max-width: 14rem;
  min-width: 0;
  flex: 1;
  transition: border-color 150ms;
}

.settings-select:focus {
  outline: none;
  border-color: var(--settings-accent);
  box-shadow: 0 0 0 2px rgba(100, 116, 139, 0.15);
}

.settings-range-wrap {
  display: flex;
  align-items: center;
  gap: var(--gap-sm);
  flex: 1;
  max-width: 14rem;
}

.settings-range {
  flex: 1;
  height: 6px;
  -webkit-appearance: none;
  appearance: none;
  background: var(--bg-inset);
  border-radius: var(--r-pill);
  outline: none;
  border: 1px solid var(--border-light);
}

.settings-range::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--settings-accent);
  border: 2px solid var(--bg-card);
  box-shadow: 0 1px 3px rgba(0,0,0,0.2);
  cursor: pointer;
}

.settings-range::-moz-range-thumb {
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--settings-accent);
  border: 2px solid var(--bg-card);
  box-shadow: 0 1px 3px rgba(0,0,0,0.2);
  cursor: pointer;
}

.settings-range-value {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
  min-width: 2.5rem;
  text-align: right;
}

.settings-number-wrap {
  display: flex;
  align-items: center;
  gap: var(--gap-xs);
}

.settings-number {
  border: 1px solid var(--border);
  border-radius: var(--r-sm);
  background: var(--bg-card);
  color: var(--text);
  padding: 0.3rem 0.4rem;
  font-size: 0.85rem;
  width: 4.5rem;
  text-align: center;
  font-variant-numeric: tabular-nums;
  transition: border-color 150ms;
}

.settings-number:focus {
  outline: none;
  border-color: var(--settings-accent);
  box-shadow: 0 0 0 2px rgba(100, 116, 139, 0.15);
}

.settings-number-unit {
  font-size: 0.82rem;
  color: var(--text-muted);
  font-weight: 500;
}

/* ===== Utility ===== */

.dim {
  opacity: 0.3;
  pointer-events: none;
}

.hidden { display: none !important; }

/* ===== Desktop Two-Column Layout (>=768px) ===== */

@media (min-width: 768px) {
  .main-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--gap-md);
    align-items: start;
  }

  .left-panel, .right-panel {
    display: flex;
    flex-direction: column;
    gap: var(--gap-md);
  }

  .header-inner {
    flex-wrap: nowrap;
    justify-content: center;
  }

  .vis-canvas {
    height: 12rem;
  }
}

/* ===== Training Card ===== */

.training-card::before { background: #14b8a6; }
.training-section { text-align: center; }

.training-progress-bar {
  width: 100%;
  height: 0.5rem;
  background: var(--bg-inset);
  border-radius: var(--r-pill);
  overflow: hidden;
  margin-bottom: var(--gap-sm);
}

.training-progress-fill {
  height: 100%;
  background: linear-gradient(90deg, #14b8a6, #0d9488);
  border-radius: var(--r-pill);
  transition: width 400ms ease;
  width: 0%;
}

.training-progress-text {
  margin: 0 0 var(--gap-sm);
  font-size: 0.88rem;
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
}

.training-reset {
  display: block;
  margin: var(--gap-sm) auto 0;
  background: none;
  border: none;
  color: var(--text-dim);
  font-size: 0.82rem;
  cursor: pointer;
  text-decoration: underline;
  padding: 0.2rem;
}
.training-reset:hover { color: var(--red); }

.training-exercise-title {
  margin: 0 0 0.2rem;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text);
}

.training-instruction {
  margin: 0 0 var(--gap-sm);
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.training-sensitivity-label {
  margin: 0 0 var(--gap-sm);
  font-size: 0.82rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: #14b8a6;
}

.training-hold-bar {
  width: 100%;
  height: 1.2rem;
  background: var(--bg-inset);
  border-radius: var(--r-pill);
  overflow: hidden;
  margin-bottom: var(--gap-sm);
  border: 1px solid var(--border-light);
}

.training-hold-fill {
  height: 100%;
  background: linear-gradient(90deg, #22c55e, #16a34a);
  border-radius: var(--r-pill);
  transition: width 100ms linear;
  width: 0%;
}

.training-timer {
  margin: 0 0 var(--gap-sm);
  font-size: 0.85rem;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  color: var(--text-muted);
}

.training-success-msg {
  margin: 0 0 var(--gap-xs);
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--green);
}

.training-advance-text {
  margin: 0;
  font-size: 0.82rem;
  color: var(--text-muted);
}

.training-stability {
  margin: 0 0 var(--gap-xs);
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  min-height: 1.1em;
}

.training-diagnostic {
  margin: 0 0 var(--gap-sm);
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.4;
}

.training-timeout-msg {
  margin: 0 0 var(--gap-xs);
  font-size: 1rem;
  font-weight: 600;
  color: var(--amber);
}

.training-timeout-btns {
  display: flex;
  gap: var(--gap-sm);
  justify-content: center;
}

.training-timeout-btns .pill-btn {
  padding: 0.4rem 1.2rem;
  background: var(--bg-card);
  color: var(--accent-text);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
}

.training-timeout-btns .pill-btn:last-child {
  color: var(--text-muted);
}

.training-start-btn {
  background: linear-gradient(135deg, #14b8a6, #0d9488) !important;
  box-shadow: 0 2px 8px rgba(20, 184, 166, 0.25) !important;
}

.training-start-btn:hover {
  box-shadow: 0 4px 14px rgba(20, 184, 166, 0.35) !important;
}

/* ===== Training Stats Row ===== */

.training-stats-row {
  display: flex;
  gap: var(--gap-sm);
  justify-content: center;
  margin-bottom: var(--gap-md);
}

.stat-box {
  flex: 1;
  max-width: 6rem;
  background: var(--bg-inset);
  border-radius: var(--r-sm);
  padding: 0.4rem 0.3rem;
  text-align: center;
  border: 1px solid var(--border-light);
}

.stat-box .stat-value {
  display: block;
  font-size: 1.3rem;
  font-weight: 800;
  font-variant-numeric: tabular-nums;
  line-height: 1.2;
  color: #0d9488;
}

.stat-box .stat-label {
  display: block;
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-dim);
  margin-top: 0.1rem;
}

.stat-streak .stat-value {
  color: var(--text-dim);
}

.stat-streak.active-streak .stat-value {
  color: #d97706;
}

/* ===== Mastery Grid ===== */

.mastery-grid {
  margin: var(--gap-sm) auto var(--gap-md);
  max-width: 12rem;
}

.mastery-header,
.mastery-row {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.mastery-header {
  margin-bottom: 0.15rem;
}

.mastery-row-label {
  width: 2.2rem;
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-dim);
  text-align: right;
  flex-shrink: 0;
  padding-right: 0.15rem;
}

.mastery-col-header {
  flex: 1;
  text-align: center;
  font-size: 0.68rem;
  font-weight: 700;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.mastery-dot {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 1.1rem;
}

.mastery-dot::after {
  content: '';
  width: 10px;
  height: 10px;
  border-radius: 50%;
  border: 2px solid var(--border);
  background: transparent;
  transition: all 200ms;
}

.mastery-dot.completed::after {
  background: #0d9488;
  border-color: #0d9488;
}

.mastery-dot.current::after {
  border-color: #14b8a6;
  box-shadow: 0 0 0 3px rgba(20, 184, 166, 0.25);
  animation: pulse-dot 1.5s ease-in-out infinite;
}

@keyframes pulse-dot {
  0%, 100% { box-shadow: 0 0 0 2px rgba(20, 184, 166, 0.2); }
  50% { box-shadow: 0 0 0 5px rgba(20, 184, 166, 0.35); }
}

/* ===== Mobile Adjustments (<768px) ===== */

@media (max-width: 767px) {
  .header-bar {
    padding: 0.4rem 0.6rem;
  }

  .header-inner {
    justify-content: center;
    font-size: 0.95rem;
  }

  .header-title {
    font-size: 1.1rem;
    width: 100%;
    text-align: center;
  }

  .main-layout {
    padding: 0.4rem 0.5rem 1.5rem;
  }

  .card {
    padding: 0.6rem 0.75rem;
  }

  .vis-canvas {
    height: 10rem;
  }

  .detected-note {
    font-size: 2rem;
  }

  .pill-btn {
    padding: 0.3rem 0.6rem;
    font-size: 0.82rem;
  }

  .stat-box .stat-value {
    font-size: 1.2rem;
  }

  .mastery-dot::after {
    width: 8px;
    height: 8px;
  }

  .mastery-grid {
    max-width: 10rem;
  }
}

/* ===== Narrow phones (<375px) ===== */

@media (max-width: 374px) {
  .header-inner {
    gap: var(--gap-xs);
    font-size: 0.85rem;
  }

  .header-title {
    font-size: 1rem;
    width: auto;
  }

  .header-logo {
    height: 1.2rem;
  }

  .header-docs-link {
    width: 1.2rem;
    height: 1.2rem;
    font-size: 0.7rem;
  }

  .pill-btn {
    padding: 0.2rem 0.4rem;
    font-size: 0.7rem;
  }

  .header-group select {
    max-width: 5rem;
    font-size: 0.75rem;
  }

  .header-group label {
    display: none;
  }

  .header-sep {
    display: none;
  }

  .ref-freq {
    display: none;
  }
}

/* ===== App Mode Toggle (Basic / Advanced) ===== */

.app-mode-toggle {
  flex-shrink: 0;
}

.voice-range-toggle {
  flex-shrink: 0;
  display: none;
}

.voice-range-toggle.visible {
  display: flex;
}

.pill-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
  pointer-events: none;
}

.chord-tone-group {
  display: inline-flex;
  align-items: center;
  gap: var(--gap-sm);
}

/* ===== Basic Mode — Hide Advanced Elements ===== */

[data-appmode="basic"] #mode-toggle-group { display: none; }
[data-appmode="basic"] .settings-card { display: none; }
[data-appmode="basic"] #training-card { display: none !important; }
[data-appmode="basic"] .chord-tone-group { display: none; }
[data-appmode="basic"] #chord-play-row { display: none !important; }
[data-appmode="basic"] .sustain-group { display: none; }
[data-appmode="basic"] .vis-tabs { display: none; }
[data-appmode="basic"] #cymatics-canvas { display: none !important; }
[data-appmode="basic"] #pitch-tracker { display: none !important; }
[data-appmode="basic"] #ref-octave { display: none; }
[data-appmode="basic"] .ref-freq { display: none; }
[data-appmode="basic"] .detected-freq { display: none; }
[data-appmode="basic"] .target-bar { display: none; }

/* Force beat canvas visible in basic mode even without .active */
[data-appmode="basic"] #beat-canvas { display: block !important; }