:root {
  --bg: #0f0e0c;
  --bg2: #1a1814;
  --bg3: #242018;
  --bg4: #2e2a22;
  --border: #3a342a;
  --border2: #4a4238;
  --text: #e8e0d0;
  --text2: #a89880;
  --text3: #6a5e4e;
  --gold: #c8953a;
  --gold2: #e8b050;

  /* chord tone colors */
  --c-root:  #4a9ede;
  --c-3rd:   #5eb854;
  --c-b3:    #5eb854;
  --c-5th:   #888070;
  --c-b7:    #e09030;
  --c-9th:   #9b7ed4;
  --c-s9:    #d45030;
  --c-13th:  #30a880;
  --c-m7:    #30a880;

  --c-root-bg:  #1a3a52;
  --c-3rd-bg:   #1e3e1a;
  --c-b7-bg:    #4a2e0a;
  --c-9th-bg:   #2e2048;
  --c-s9-bg:    #4a1a0a;
  --c-13th-bg:  #0a3028;
  --c-m7-bg:    #0a3028;
}

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

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Source Sans 3', sans-serif;
  font-size: 14px;
  line-height: 1.6;
}

/* ── HEADER ── */
.site-header {
  padding: 48px 40px 32px;
  border-bottom: 1px solid var(--border);
  background: linear-gradient(180deg, #1a1510 0%, var(--bg) 100%);
  position: relative;
  overflow: hidden;
}
.site-header::before {
  content: '♭♯♭♯♭♯♭♯♭♯♭♯♭♯♭♯♭♯♭♯♭♯♭♯♭♯♭♯♭♯♭♯';
  position: absolute; top: 12px; left: 0; right: 0;
  font-size: 11px; letter-spacing: 6px; color: var(--border2);
  text-align: center; pointer-events: none;
}
.site-header h1 {
  font-family: 'Playfair Display', serif;
  font-size: 42px; font-weight: 900;
  color: var(--gold2);
  letter-spacing: -0.5px;
  margin-bottom: 6px;
}
.site-header .subtitle {
  font-size: 15px; color: var(--text2); font-weight: 300;
  letter-spacing: 0.5px;
}

/* ── NAV ── */
.key-nav {
  display: flex; flex-wrap: wrap; gap: 6px;
  padding: 16px 40px;
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 100;
}
.key-nav a {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px; font-weight: 500;
  color: var(--text2);
  text-decoration: none;
  padding: 4px 10px;
  border: 1px solid var(--border2);
  border-radius: 4px;
  transition: all 0.15s;
}
.key-nav a:hover {
  color: var(--gold2); border-color: var(--gold);
  background: rgba(200,149,58,0.08);
}

/* ── COLOR LEGEND ── */
.legend {
  display: flex; flex-wrap: wrap; gap: 8px;
  padding: 16px 40px;
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
}
.legend-item {
  display: flex; align-items: center; gap: 6px;
  font-size: 12px; color: var(--text2);
}
.legend-dot {
  width: 10px; height: 10px; border-radius: 50%;
}

/* ── KEY SECTION ── */
.key-section {
  padding: 40px 40px 48px;
  border-bottom: 1px solid var(--border);
}
.key-section:last-child { border-bottom: none; }

.key-header {
  display: flex; align-items: baseline; gap: 16px;
  margin-bottom: 6px;
}
.key-title {
  font-family: 'Playfair Display', serif;
  font-size: 36px; font-weight: 900;
  color: var(--gold2);
}
.key-meta {
  font-size: 12px; color: var(--text3);
  font-family: 'IBM Plex Mono', monospace;
}
.key-info {
  font-size: 13px; color: var(--text2);
  margin-bottom: 24px;
  font-family: 'IBM Plex Mono', monospace;
  padding: 8px 14px;
  background: var(--bg2);
  border-left: 3px solid var(--gold);
  border-radius: 0 4px 4px 0;
  display: inline-block;
}
.key-info span { color: var(--gold2); }

/* ── CHORD GRID ── */
.chord-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 16px;
}

/* ── CHORD CARD ── */
.chord-card {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: visible;
  transition: border-color 0.15s;
}
.chord-card:hover { border-color: var(--border2); }
.chord-card.card-ii { border-left: 3px solid #6060b0; }
.chord-card.card-v  { border-left: 3px solid #a04030; }
.chord-card.card-i  { border-left: 3px solid #208060; }

.chord-card-header {
  padding: 12px 14px 8px;
  border-bottom: 1px solid var(--border);
  display: flex; justify-content: space-between; align-items: baseline;
}
.chord-name {
  font-family: 'Playfair Display', serif;
  font-size: 20px; font-weight: 700;
  color: var(--text);
}
.chord-role {
  font-size: 11px; font-weight: 600;
  font-family: 'IBM Plex Mono', monospace;
  padding: 2px 8px; border-radius: 10px;
}
.role-dom  { color: var(--gold2);  background: rgba(200,149,58,0.12); }
.role-ii   { color: #9090e0; background: rgba(90,90,180,0.15); }
.role-v    { color: #e07060; background: rgba(180,60,40,0.15); }
.role-i    { color: #50c890; background: rgba(30,140,90,0.15); }

.chord-card-body { padding: 12px 14px; }

/* ── PIANO ── */
.piano-wrap {
  margin-bottom: 12px;
  position: relative;
}

.piano {
  position: relative;
  height: 86px;
  user-select: none;
}

.key-w {
  position: absolute;
  bottom: 0;
  width: 26px;
  height: 82px;
  background: #f0ece4;
  border: 1px solid #888;
  border-radius: 0 0 4px 4px;
  cursor: default;
  transition: filter 0.1s;
  display: flex; flex-direction: column;
  align-items: center; justify-content: flex-end;
  padding-bottom: 5px;
}
.key-w.lit {
  cursor: pointer;
}
.key-w .note-name {
  font-size: 8px; font-weight: 600;
  color: rgba(0,0,0,0.4);
  pointer-events: none;
}
.key-w.lit .note-name { color: rgba(0,0,0,0.6); }
.key-w .role-badge {
  font-size: 8px; font-weight: 700;
  position: absolute; top: 10px;
  pointer-events: none;
}

.key-b {
  position: absolute;
  top: 0;
  width: 16px;
  height: 50px;
  background: #1a1814;
  border: 1px solid #000;
  border-radius: 0 0 3px 3px;
  z-index: 2;
  cursor: default;
  transition: filter 0.1s;
  display: flex; flex-direction: column;
  align-items: center; justify-content: flex-end;
  padding-bottom: 3px;
}
.key-b.lit { cursor: pointer; }
.key-b .role-badge {
  font-size: 7px; font-weight: 700;
  color: rgba(255,255,255,0.9);
  pointer-events: none;
  position: absolute; top: 6px;
}

/* lit colors - white keys */
.key-w.lit-root  { background: #6ab4e8; border-color: var(--c-root); }
.key-w.lit-3rd   { background: #80cc74; border-color: var(--c-3rd); }
.key-w.lit-b3    { background: #80cc74; border-color: var(--c-b3); }
.key-w.lit-b5    { background: #d87848; border-color: var(--c-b5, #c05830); }
.key-w.lit-5th   { background: #c0b8a8; border-color: #666; }
.key-w.lit-b7    { background: #f0a840; border-color: var(--c-b7); }
.key-w.lit-9th   { background: #b098e8; border-color: var(--c-9th); }
.key-w.lit-s9    { background: #e87050; border-color: var(--c-s9); }
.key-w.lit-13th  { background: #50c8a0; border-color: var(--c-13th); }
.key-w.lit-m7    { background: #50c8a0; border-color: var(--c-m7); }
.key-w.lit-cb    { background: #f0a840; border-color: var(--c-b7); }

/* lit colors - black keys */
.key-b.lit-root  { background: #2060a0; border-color: var(--c-root); }
.key-b.lit-3rd   { background: #206820; border-color: var(--c-3rd); }
.key-b.lit-b3    { background: #206820; border-color: var(--c-b3); }
.key-b.lit-b5    { background: #803018; border-color: var(--c-b5, #c05830); }
.key-b.lit-b7    { background: #805010; border-color: var(--c-b7); }
.key-b.lit-9th   { background: #503090; border-color: var(--c-9th); }
.key-b.lit-s9    { background: #902010; border-color: var(--c-s9); }
.key-b.lit-13th  { background: #106048; border-color: var(--c-13th); }
.key-b.lit-m7    { background: #106048; border-color: var(--c-m7); }

/* ── VOICINGS ── */
.voicings {
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 8px;
  margin-top: 8px;
}
.voicing-box {
  background: var(--bg3);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 8px 10px;
}
.voicing-label {
  font-size: 10px; font-weight: 600;
  text-transform: uppercase; letter-spacing: 0.08em;
  color: var(--text3); margin-bottom: 4px;
}
.voicing-label span { color: var(--gold); }
.voicing-notes {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px; color: var(--text);
  display: flex; flex-wrap: wrap; gap: 4px;
}
.vn {
  padding: 2px 6px; border-radius: 4px;
  font-weight: 500; font-size: 11px;
  cursor: default;
}
.vn-root  { background: var(--c-root-bg);  color: var(--c-root); }
.vn-3rd   { background: var(--c-3rd-bg);   color: var(--c-3rd); }
.vn-b3    { background: var(--c-3rd-bg);   color: var(--c-b3); }
.vn-b7    { background: var(--c-b7-bg);    color: var(--c-b7); }
.vn-9th   { background: var(--c-9th-bg);   color: var(--c-9th); }
.vn-s9    { background: var(--c-s9-bg);    color: var(--c-s9); }
.vn-13th  { background: var(--c-13th-bg);  color: var(--c-13th); }
.vn-m7    { background: var(--c-m7-bg);    color: var(--c-m7); }
.vn-5th   { background: var(--bg4);        color: var(--text3); }

.voicing-tip {
  font-size: 11px; color: var(--text3); margin-top: 6px;
  font-style: italic; line-height: 1.4;
}

/* ── TOOLTIP ── */
.tooltip {
  position: fixed;
  z-index: 9999;
  pointer-events: none;
  opacity: 0;
  transform: translateY(6px);
  transition: opacity 0.15s, transform 0.15s;
  max-width: 220px;
}
.tooltip.show {
  opacity: 1;
  transform: translateY(0);
}
.tooltip-inner {
  background: #1e1c18;
  border: 1px solid var(--gold);
  border-radius: 6px;
  padding: 10px 12px;
  box-shadow: 0 8px 24px rgba(0,0,0,0.6);
}
.tt-note {
  font-family: 'Playfair Display', serif;
  font-size: 18px; font-weight: 700;
  margin-bottom: 2px;
}
.tt-role {
  font-size: 11px; font-weight: 600;
  font-family: 'IBM Plex Mono', monospace;
  margin-bottom: 6px; padding: 2px 6px;
  border-radius: 4px; display: inline-block;
}
.tt-desc {
  font-size: 12px; color: var(--text2);
  line-height: 1.5;
}
.tt-interval {
  font-size: 11px; color: var(--text3);
  font-family: 'IBM Plex Mono', monospace;
  margin-top: 4px;
}

/* ── II-V-I SECTION ── */
.progression-section {
  margin-top: 32px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
}
.section-label {
  font-size: 11px; font-weight: 600;
  text-transform: uppercase; letter-spacing: 0.1em;
  color: var(--text3); margin-bottom: 14px;
}
.progression-flow {
  display: flex; align-items: center; gap: 10px;
  flex-wrap: wrap; margin-bottom: 20px;
}
.prog-step {
  display: flex; flex-direction: column;
  align-items: center; gap: 3px;
}
.prog-step-chord {
  font-family: 'Playfair Display', serif;
  font-size: 16px; font-weight: 700;
}
.prog-step-role {
  font-size: 10px; font-family: 'IBM Plex Mono', monospace;
  color: var(--text3);
}
.prog-arrow {
  font-size: 18px; color: var(--border2);
  margin-top: -8px;
}
.vl-row {
  display: flex; align-items: center; gap: 8px;
  font-size: 12px; font-family: 'IBM Plex Mono', monospace;
  color: var(--text2); margin-bottom: 4px; flex-wrap: wrap;
}
.vl-note { font-weight: 600; color: var(--text); }
.vl-sep { color: var(--border2); }

@media print {
  .key-nav { display: none; }
  .chord-card { break-inside: avoid; }
  .key-section { break-before: page; }
}


/* ── TABS ── */
.tab-bar {
  display: flex; gap: 0;
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
  padding: 0 40px;
  position: sticky; top: 0; z-index: 200;
  overflow-x: auto;
}
.tab-btn {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px; font-weight: 500;
  color: var(--text3);
  background: none; border: none;
  border-bottom: 2px solid transparent;
  padding: 14px 18px 12px;
  cursor: pointer; white-space: nowrap;
  flex-shrink: 0;
  transition: all 0.15s;
}
.form-bar-hint { display: none; }
.tab-btn:hover { color: var(--text2); }
.tab-btn.active { color: var(--gold2); border-bottom-color: var(--gold2); }

.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* ── SECONDARY NAV (key nav inside workbook tab) ── */
.key-nav {
  display: flex; flex-wrap: wrap; gap: 6px;
  padding: 12px 40px;
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
}
.key-nav a {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px; font-weight: 500;
  color: var(--text2);
  text-decoration: none;
  padding: 4px 10px;
  border: 1px solid var(--border2);
  border-radius: 4px;
  transition: all 0.15s;
}
.key-nav a:hover { color: var(--gold2); border-color: var(--gold); background: rgba(200,149,58,0.08); }

/* ── PROGRESSION PAGE ── */
.prog-page { padding: 0 0 60px; }

.prog-top-nav {
  display: flex; flex-wrap: wrap; gap: 6px;
  padding: 12px 40px;
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
  position: sticky; top: 48px; z-index: 100;
}
.prog-top-nav a {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px; font-weight: 500;
  color: var(--text2); text-decoration: none;
  padding: 3px 9px; border: 1px solid var(--border2); border-radius: 4px;
  transition: all 0.15s;
}
.prog-top-nav a:hover { color: var(--gold2); border-color: var(--gold); background: rgba(200,149,58,0.08); }

.prog-group {
  padding: 40px 40px 0;
  border-top: 1px solid var(--border);
  margin-top: 0;
}
.prog-group:first-child { border-top: none; }

.prog-group-title {
  font-family: 'Playfair Display', serif;
  font-size: 28px; font-weight: 900;
  color: var(--gold2); margin-bottom: 6px;
}
.prog-group-desc {
  font-size: 13px; color: var(--text2);
  line-height: 1.6; max-width: 680px;
  margin-bottom: 28px;
}

/* ── PROGRESSION CARD ── */
.prog-card {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 10px;
  margin-bottom: 32px;
  overflow: hidden;
}
.prog-card-header {
  padding: 16px 20px 12px;
  border-bottom: 1px solid var(--border);
  display: flex; justify-content: space-between; align-items: flex-start;
  flex-wrap: wrap; gap: 8px;
}
.prog-card-name {
  font-family: 'Playfair Display', serif;
  font-size: 22px; font-weight: 700; color: var(--text);
}
.prog-card-aka {
  font-size: 11px; color: var(--text3);
  font-family: 'IBM Plex Mono', monospace;
  margin-top: 2px;
}
.prog-card-tag {
  font-size: 11px; font-weight: 600;
  font-family: 'IBM Plex Mono', monospace;
  padding: 3px 10px; border-radius: 10px;
  background: rgba(200,149,58,0.1); color: var(--gold2);
  align-self: flex-start;
}
.prog-card-body { padding: 20px; }
.prog-card-desc {
  font-size: 13px; color: var(--text2);
  line-height: 1.7; margin-bottom: 20px;
  max-width: 700px;
}

/* ── FORM DISPLAY (12-bar etc) ── */
.form-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 6px;
  margin-bottom: 20px;
}
.form-bar {
  background: var(--bg3);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 8px 10px;
  min-height: 64px;
}
.form-bar.turnaround { border-color: #5a4010; background: #1e1808; }
.form-bar.highlight  { border-color: #304060; background: #101828; }
.form-bar.alt-color  { border-color: #205030; background: #0a1e10; }
.bar-num {
  font-size: 9px; color: var(--text3);
  font-family: 'IBM Plex Mono', monospace;
  margin-bottom: 3px;
}
.bar-chord {
  font-family: 'Playfair Display', serif;
  font-size: 15px; font-weight: 700; color: var(--text);
  line-height: 1.2;
}
.bar-quality {
  font-size: 10px; color: var(--text3);
  font-family: 'IBM Plex Mono', monospace;
  margin-top: 2px;
}
.bar-function {
  font-size: 9px; font-weight: 600;
  font-family: 'IBM Plex Mono', monospace;
  margin-top: 4px; padding: 1px 5px;
  border-radius: 3px; display: inline-block;
}
.fn-i   { background: rgba(30,140,90,0.2);  color: #50c890; }
.fn-iv  { background: rgba(180,120,20,0.2); color: #d4a040; }
.fn-v   { background: rgba(180,60,40,0.2);  color: #e07060; }
.fn-ii  { background: rgba(90,90,180,0.2);  color: #9090e0; }
.fn-vi  { background: rgba(160,60,160,0.2); color: #c080c0; }
.fn-iii { background: rgba(60,120,180,0.2); color: #60a8d8; }
.fn-sub { background: rgba(100,60,20,0.2);  color: #c08040; }
.fn-bdim{ background: rgba(80,40,80,0.2);   color: #a060a0; }

/* ── CHORD FLOW (linear progression display) ── */
.chord-flow {
  display: flex; align-items: stretch; flex-wrap: wrap; gap: 6px;
  margin-bottom: 16px;
}
.flow-item {
  display: flex; flex-direction: column;
  align-items: center; gap: 4px;
  min-width: 72px;
}
.flow-chord-name {
  font-family: 'Playfair Display', serif;
  font-size: 16px; font-weight: 700;
  padding: 8px 12px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--bg3);
  text-align: center; width: 100%;
}
.flow-chord-role {
  font-size: 10px; color: var(--text3);
  font-family: 'IBM Plex Mono', monospace;
}
.flow-arrow {
  font-size: 20px; color: var(--border2);
  align-self: center; padding-top: 8px;
}
.flow-item.fi-ii .flow-chord-name  { color: #9090e0; border-color: #404080; background: #14142a; }
.flow-item.fi-v  .flow-chord-name  { color: #e07060; border-color: #602010; background: #1e100a; }
.flow-item.fi-i  .flow-chord-name  { color: #50c890; border-color: #205040; background: #0a1e14; }
.flow-item.fi-vi .flow-chord-name  { color: #c080c0; border-color: #602060; background: #1a0a1a; }
.flow-item.fi-iii .flow-chord-name { color: #60a8d8; border-color: #204060; background: #0a1420; }
.flow-item.fi-iv  .flow-chord-name { color: #d4a040; border-color: #604010; background: #1e1408; }
.flow-item.fi-sub .flow-chord-name { color: #c08040; border-color: #604010; background: #1e1408; }

/* ── VOICE LEADING TABLE ── */
.vl-table {
  width: 100%; border-collapse: collapse;
  margin-bottom: 16px; font-size: 12px;
}
.vl-table th {
  text-align: left; padding: 6px 10px;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10px; font-weight: 600;
  text-transform: uppercase; letter-spacing: 0.06em;
  color: var(--text3);
  border-bottom: 1px solid var(--border);
}
.vl-table td {
  padding: 6px 10px;
  border-bottom: 1px solid var(--border);
  font-family: 'IBM Plex Mono', monospace;
}
.vl-table tr:last-child td { border-bottom: none; }
.vl-table .vl-note-cell { font-weight: 600; color: var(--text); }
.vl-arrow-cell { color: var(--text3); }

/* ── COMPARISON BOX ── */
.compare-grid {
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 12px; margin-bottom: 16px;
}
.compare-box {
  background: var(--bg3); border: 1px solid var(--border);
  border-radius: 8px; padding: 12px 14px;
}
.compare-label {
  font-size: 10px; font-weight: 600; text-transform: uppercase;
  letter-spacing: 0.08em; color: var(--text3); margin-bottom: 8px;
}
.compare-chords {
  font-family: 'Playfair Display', serif;
  font-size: 14px; color: var(--text);
  line-height: 1.8;
}
.compare-note {
  font-size: 11px; color: var(--text3); margin-top: 6px;
  font-family: 'IBM Plex Mono', monospace; line-height: 1.4;
}

/* ── THEORY NOTE ── */
.theory-note {
  background: var(--bg3); border-left: 3px solid var(--gold);
  border-radius: 0 6px 6px 0; padding: 10px 14px;
  font-size: 12px; color: var(--text2); line-height: 1.6;
  margin-bottom: 16px;
}
.theory-note strong { color: var(--gold2); }

/* ── KEY SELECTOR ── */
.key-selector {
  display: flex; flex-wrap: wrap; gap: 6px;
  margin-bottom: 20px;
}
.key-btn {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px; font-weight: 500;
  padding: 4px 10px; border-radius: 4px;
  border: 1px solid var(--border2);
  background: var(--bg3); color: var(--text2);
  cursor: pointer; transition: all 0.15s;
}
.key-btn:hover { color: var(--gold2); border-color: var(--gold); }
.key-btn.active { background: rgba(200,149,58,0.15); color: var(--gold2); border-color: var(--gold); }
.key-display { display: none; }
.key-display.active { display: block; }

.prog-subsection-title {
  font-size: 13px; font-weight: 600; color: var(--text);
  margin: 16px 0 10px;
  display: flex; align-items: center; gap: 8px;
}
.prog-subsection-title::after {
  content: ''; flex: 1; height: 1px; background: var(--border);
}

.prog-subgroup {
  margin-top: 36px;
  padding-top: 28px;
  border-top: 1px solid var(--border);
  scroll-margin-top: 100px;
}
.prog-subgroup-title {
  font-size: 18px; font-weight: 700; color: var(--gold2);
  margin-bottom: 8px;
}
.prog-subgroup-desc {
  font-size: 14px; color: var(--text2); line-height: 1.55;
  margin-bottom: 20px; max-width: 680px;
}
.prog-group { scroll-margin-top: 100px; }

/* ── Form bar expanded for piano panels ── */
.form-grid {
  grid-template-columns: repeat(4, 1fr);
}
.form-bar {
  min-height: auto;
}


/* ── PLAY BUTTONS ── */
.play-btn {
  background: rgba(200,149,58,0.08);
  border: 1px solid var(--gold);
  color: var(--gold);
  border-radius: 4px;
  padding: 2px 8px;
  font-size: 11px;
  font-family: 'IBM Plex Mono', monospace;
  cursor: pointer;
  transition: all 0.15s;
  flex-shrink: 0;
  line-height: 1.8;
}
.play-btn:hover { background: rgba(200,149,58,0.22); color: var(--gold2); }
.play-btn.is-playing { background: var(--gold); color: #0f0e0c; border-color: var(--gold2); }

.play-prog-btn {
  background: rgba(200,149,58,0.08);
  border: 1px solid var(--border2);
  color: var(--text2);
  border-radius: 5px;
  padding: 5px 14px;
  font-size: 11px;
  font-family: 'IBM Plex Mono', monospace;
  cursor: pointer;
  transition: all 0.15s;
  white-space: nowrap;
}
.play-prog-btn:hover { border-color: var(--gold); color: var(--gold2); }
.play-prog-btn.is-playing { border-color: var(--gold); background: rgba(200,149,58,0.15); color: var(--gold2); }

/* Highlight the bar currently sounding during progression playback */
.playing-now { outline: 2px solid var(--gold2); outline-offset: -2px; border-radius: 6px; }

/* ── VOICING PICKER (floating, bottom-right) ── */
#voicing-picker {
  position: fixed;
  bottom: 20px;
  right: 20px;
  z-index: 500;
  display: flex;
  align-items: center;
  gap: 6px;
  background: var(--bg2);
  border: 1px solid var(--border2);
  border-radius: 8px;
  padding: 8px 12px;
  box-shadow: 0 4px 20px rgba(0,0,0,0.55);
}
.vp-label {
  font-size: 10px;
  color: var(--text3);
  font-family: 'IBM Plex Mono', monospace;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  margin-right: 4px;
  user-select: none;
}
.vp-btn {
  background: none;
  border: 1px solid var(--border2);
  color: var(--text2);
  border-radius: 4px;
  padding: 3px 11px;
  font-size: 11px;
  font-family: 'IBM Plex Mono', monospace;
  cursor: pointer;
  transition: all 0.15s;
}
.vp-btn:hover { color: var(--gold2); border-color: var(--gold); }
.vp-btn.active {
  background: rgba(200,149,58,0.15);
  color: var(--gold2);
  border-color: var(--gold);
}

/* ══════════════════════════════════════════════════════
   THEORY TAB
   ══════════════════════════════════════════════════════ */

.theory-page { padding: 0 40px 100px; }

/* ── Chapter nav ── */
.theory-nav {
  display: flex; gap: 4px; flex-wrap: wrap;
  padding: 10px 40px;
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
  position: sticky; top: 48px; z-index: 100;
}
.theory-nav a {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px; font-weight: 600;
  color: var(--text2); text-decoration: none;
  padding: 4px 12px; border-radius: 4px;
  border: 1px solid var(--border2);
  transition: all 0.15s;
}
.theory-nav a:hover { color: var(--gold2); border-color: var(--gold); background: rgba(200,149,58,0.08); }

/* ── Chapter ── */
.theory-chapter {
  padding: 56px 0 40px;
  border-bottom: 1px solid var(--border);
}
.theory-chapter:last-child { border-bottom: none; }
.theory-chapter-title {
  font-family: 'Playfair Display', serif;
  font-size: 36px; font-weight: 900;
  color: var(--gold2); margin-bottom: 6px;
}
.theory-chapter-sub {
  font-size: 12px; font-family: 'IBM Plex Mono', monospace;
  color: var(--text3); letter-spacing: 0.08em; text-transform: uppercase;
  margin-bottom: 18px;
}
.theory-chapter-lead {
  font-size: 15px; color: var(--text2); line-height: 1.75;
  max-width: 820px; margin-bottom: 48px;
}

/* ── Section ── */
.theory-section { margin-bottom: 40px; max-width: 820px; }
.theory-section-title {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px; font-weight: 700;
  text-transform: uppercase; letter-spacing: 0.12em;
  color: var(--gold); margin-bottom: 16px;
  padding-bottom: 7px;
  border-bottom: 1px solid var(--border);
  display: flex; align-items: center; gap: 10px;
}
.theory-section-num {
  background: rgba(200,149,58,0.12);
  color: var(--gold2); border-radius: 3px;
  padding: 1px 7px; font-size: 10px;
}

/* ── Body prose ── */
.theory-body {
  font-size: 14px; color: var(--text2); line-height: 1.8;
}
.theory-body p { margin-bottom: 14px; }
.theory-body strong { color: var(--text); font-weight: 600; }
.theory-body em { color: var(--gold2); font-style: normal; font-weight: 600; }

/* ── Callout / Rule / Formula boxes ── */
.theory-callout {
  background: var(--bg2);
  border-left: 3px solid var(--gold);
  border-radius: 0 6px 6px 0;
  padding: 14px 18px; margin: 18px 0;
  font-size: 13px; color: var(--text2); line-height: 1.7;
}
.theory-callout strong { color: var(--gold2); }

.theory-rule {
  background: var(--bg3); border: 1px solid var(--border);
  border-radius: 6px; padding: 10px 16px; margin: 10px 0;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px; color: var(--text); line-height: 1.6;
}
.theory-rule .r-label {
  font-size: 10px; color: var(--text3); margin-bottom: 4px;
  text-transform: uppercase; letter-spacing: 0.08em;
}

/* ── Two-column comparison ── */
.theory-cols {
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 16px; margin: 16px 0;
}
@media (max-width: 700px) { .theory-cols { grid-template-columns: 1fr; } }
.theory-col-box {
  background: var(--bg2); border: 1px solid var(--border);
  border-radius: 6px; padding: 14px 16px;
}
.theory-col-label {
  font-size: 10px; font-weight: 700; text-transform: uppercase;
  letter-spacing: 0.08em; color: var(--text3); margin-bottom: 8px;
}
.theory-col-body { font-size: 13px; color: var(--text2); line-height: 1.7; }
.theory-col-body strong { color: var(--text); }

/* ── Tables ── */
.theory-table {
  width: 100%; border-collapse: collapse;
  font-size: 12px; font-family: 'IBM Plex Mono', monospace;
  margin: 14px 0;
}
.theory-table th {
  background: var(--bg3); color: var(--text3);
  font-size: 10px; text-transform: uppercase; letter-spacing: 0.08em;
  padding: 7px 12px; text-align: left;
  border-bottom: 1px solid var(--border2);
}
.theory-table td {
  padding: 7px 12px; color: var(--text2);
  border-bottom: 1px solid var(--border);
  vertical-align: top; line-height: 1.5;
}
.theory-table tr:last-child td { border-bottom: none; }
.theory-table .hl td { color: var(--text); }
.theory-table .gold td:first-child { color: var(--gold2); font-weight: 600; }

/* ── Tag pills ── */
.th-tag {
  display: inline-block; font-size: 10px; font-weight: 700;
  font-family: 'IBM Plex Mono', monospace;
  padding: 2px 8px; border-radius: 10px;
  margin-right: 4px; vertical-align: middle;
}
.th-blues { background: rgba(180,60,40,0.15); color: #e07060; }
.th-jazz  { background: rgba(200,149,58,0.12); color: var(--gold2); }
.th-rnb   { background: rgba(80,200,160,0.12); color: #50c890; }

/* ══════════════════════════════════════════════════════════════════
   RESPONSIVE LAYOUT
   Breakpoints:
     ≤ 768px  tablet — tighten padding, loosen grids
     ≤ 600px  phone  — single-column, scrollable pianos, compact nav
   ══════════════════════════════════════════════════════════════════ */

/* ── Tablet (≤ 768px) ──────────────────────────────────────────── */
@media (max-width: 768px) {

  .site-header         { padding: 32px 20px 24px; }
  .site-header h1      { font-size: 34px; }

  .tab-bar             { padding: 0 16px; }
  .key-nav             { padding: 10px 16px; }
  .legend              { padding: 10px 16px; }
  .prog-top-nav        { padding: 10px 16px; }
  .theory-nav          { padding: 8px 16px; }

  .key-section         { padding: 28px 20px 36px; }
  .prog-group          { padding: 28px 20px 0; }
  .theory-page         { padding: 0 20px 80px; }
  .theory-chapter      { padding: 36px 0 28px; }

  /* Chord cards: allow narrower cards before stacking to 1 col */
  .chord-grid          { grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); }

  /* Voicing picker: slightly smaller */
  #voicing-picker      { padding: 6px 10px; gap: 5px; }
}

/* ── Phone (≤ 600px) ───────────────────────────────────────────── */
@media (max-width: 600px) {

  /* ── Header ── */
  .site-header         { padding: 20px 16px 16px; }
  .site-header h1      { font-size: 26px; letter-spacing: 0; }
  .site-header .subtitle { font-size: 12px; line-height: 1.6; }
  .site-header::before { display: none; }  /* hide decorative ♭♯ row */

  /* ── Tabs ── */
  .tab-bar             {
    padding: 0 8px;
    overflow-x: auto;
    flex-wrap: nowrap;
    -webkit-overflow-scrolling: touch;
  }
  .tab-btn             { padding: 11px 13px 9px; font-size: 11px; flex-shrink: 0; }

  /* ── Key nav ── */
  .key-nav             { padding: 8px 12px; gap: 5px; }
  .key-nav a           { font-size: 11px; padding: 3px 8px; }

  /* ── Legend ── */
  .legend              { padding: 8px 12px; gap: 6px; }
  /* Remove the "auto" left-push on the last legend item */
  .legend-item:last-child { margin-left: 0; font-size: 11px; }

  /* ── Workbook sections ── */
  .key-section         { padding: 18px 12px 24px; }
  .key-title           { font-size: 26px; }
  .key-meta            { font-size: 11px; }
  .key-info            { font-size: 11px; display: block; padding: 6px 10px; }

  /* Chord cards: 1 column */
  .chord-grid          { grid-template-columns: 1fr; gap: 10px; }

  /* Piano: scroll horizontally if it ever overflows the card */
  .piano-wrap          { overflow-x: auto; -webkit-overflow-scrolling: touch; }

  /* LH / RH boxes: stack vertically */
  .voicings            { grid-template-columns: 1fr; }

  /* Chord card header: allow role badge to wrap below */
  .chord-card-header   { flex-wrap: wrap; gap: 4px; }

  /* ── Progression top nav ── */
  /* Section links wrap, key selector gets its own scrollable row */
  .prog-top-nav        { flex-wrap: wrap; padding: 8px 12px; gap: 4px; }

  /* Push key selector to its own full-width row, scroll horizontally */
  .prog-top-nav > div:last-child {
    width: 100%;
    margin-left: 0;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    flex-wrap: nowrap;
    padding-bottom: 4px;
  }

  /* ── Progression groups / cards ── */
  .prog-group          { padding: 18px 12px 0; }
  .prog-group-title    { font-size: 22px; }
  .prog-group-desc     { font-size: 13px; }
  .prog-card-header    { flex-wrap: wrap; gap: 6px; }
  .prog-card-name      { font-size: 14px; }
  .prog-card-desc      { font-size: 13px; }
  .theory-note         { font-size: 12px; }
  .prog-subsection-title { font-size: 10px; }

  /* ── 12-bar form grid ── */
  /* 2 columns — tap bar header to expand voicing */
  .form-grid           { grid-template-columns: repeat(2, 1fr); gap: 5px; }
  .form-bar            { padding: 6px 8px; min-height: auto; cursor: pointer; }
  .form-bar .form-bar-panel { display: none; }
  .form-bar.expanded .form-bar-panel { display: block; }
  .bar-chord-row       { display: flex; align-items: baseline; justify-content: space-between; gap: 6px; }
  .form-bar-hint       {
    font-size: 9px;
    font-family: var(--font-mono, 'IBM Plex Mono', monospace);
    color: var(--text3);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    flex-shrink: 0;
  }

  /* ── Chord flow (ii-V-I etc.) ── */
  /* Scroll horizontally instead of wrapping into a mess */
  .chord-flow-container {
    flex-wrap: nowrap !important;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    gap: 8px !important;
    padding-bottom: 8px;
  }
  .flow-item           { min-width: 200px !important; }

  /* Voice-leading table */
  .vl-table th,
  .vl-table td         { font-size: 11px; padding: 5px 6px; }

  /* ── Theory tab ── */
  .theory-nav          { overflow-x: auto; flex-wrap: nowrap; padding: 8px 12px; }
  .theory-nav a        { flex-shrink: 0; }
  .theory-page         { padding: 0 12px 80px; }
  .theory-chapter      { padding: 22px 0 18px; }
  .theory-chapter-title { font-size: 24px; }
  .theory-chapter-sub  { font-size: 11px; }
  .theory-chapter-lead { font-size: 13px; margin-bottom: 28px; }
  .theory-section-title { font-size: 10px; letter-spacing: 0.08em; }
  .theory-body         { font-size: 13px; }
  .theory-callout      { font-size: 12px; padding: 10px 14px; }
  .theory-rule         { font-size: 11px; padding: 8px 12px; }
  .theory-table        { font-size: 11px; }
  .theory-table th,
  .theory-table td     { padding: 5px 8px; }

  /* ── Voicing picker: hide label, compact ── */
  #voicing-picker      { bottom: 10px; right: 10px; padding: 5px 8px; gap: 4px; }
  .vp-label            { display: none; }
  .vp-btn              { padding: 3px 9px; font-size: 10px; }

  /* ── Touch-friendly play buttons ── */
  .play-btn            { min-height: 30px; padding: 4px 12px; font-size: 12px; }
  .play-prog-btn       { min-height: 30px; padding: 5px 12px; }
}

/* ══════════════════════════════════════════════════════════════════
   PRACTICE TAB
   ══════════════════════════════════════════════════════════════════ */

.practice-page { padding: 0 40px 100px; }

/* ── Section ── */
.practice-section {
  padding: 40px 0 36px;
  border-bottom: 1px solid var(--border);
}
.practice-section:last-child { border-bottom: none; }

.practice-section-title {
  font-family: 'Playfair Display', serif;
  font-size: 28px; font-weight: 900;
  color: var(--gold2); margin-bottom: 6px;
}
.practice-section-desc {
  font-size: 13px; color: var(--text2);
  line-height: 1.6; max-width: 600px; margin-bottom: 28px;
}

/* ── Metronome ── */
.metro-controls {
  display: flex; flex-wrap: wrap; align-items: center; gap: 20px;
  margin-bottom: 24px;
}

.metro-bpm-display {
  font-family: 'Playfair Display', serif;
  font-size: 72px; font-weight: 900;
  color: var(--gold2); line-height: 1;
  min-width: 120px; text-align: center;
}
.metro-bpm-label {
  font-size: 11px; color: var(--text3);
  font-family: 'IBM Plex Mono', monospace;
  text-transform: uppercase; letter-spacing: 0.1em;
  text-align: center; margin-top: 2px;
}

.metro-btn-group { display: flex; flex-direction: column; gap: 8px; }

.metro-btn {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px; font-weight: 600;
  cursor: pointer; border-radius: 6px;
  padding: 8px 20px; border: 1px solid var(--border2);
  transition: all 0.15s; background: none; color: var(--text2);
  white-space: nowrap;
}
.metro-btn:hover { border-color: var(--gold); color: var(--gold2); background: rgba(200,149,58,0.08); }
.metro-btn.active { background: var(--gold); color: #0f0e0c; border-color: var(--gold2); font-weight: 700; }
.metro-btn.tap { border-color: var(--border2); min-width: 110px; }

.metro-slider-group { display: flex; flex-direction: column; gap: 6px; min-width: 200px; }
.metro-slider-label {
  font-size: 10px; color: var(--text3);
  font-family: 'IBM Plex Mono', monospace;
  text-transform: uppercase; letter-spacing: 0.08em;
}
.metro-slider {
  -webkit-appearance: none; appearance: none;
  width: 100%; height: 4px;
  background: var(--border2); border-radius: 2px; cursor: pointer;
}
.metro-slider::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none;
  width: 18px; height: 18px; border-radius: 50%;
  background: var(--gold); cursor: pointer;
}
.metro-slider::-moz-range-thumb {
  width: 18px; height: 18px; border-radius: 50%;
  background: var(--gold); cursor: pointer; border: none;
}

/* ── Beat indicator ── */
.metro-beats {
  display: flex; gap: 10px; align-items: center;
  margin-bottom: 20px; flex-wrap: wrap;
}
.metro-beat-dot {
  width: 18px; height: 18px; border-radius: 50%;
  background: var(--bg3); border: 2px solid var(--border2);
  transition: background 0.05s, border-color 0.05s;
  flex-shrink: 0;
}
.metro-beat-dot.lit-accent {
  background: var(--gold2); border-color: var(--gold2);
  box-shadow: 0 0 12px rgba(200,149,58,0.6);
}
.metro-beat-dot.lit-beat {
  background: var(--text2); border-color: var(--text);
}

/* ── Time signature picker ── */
.metro-timesig {
  display: flex; gap: 6px; flex-wrap: wrap;
}
.metro-timesig-btn {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px; font-weight: 600;
  background: none; border: 1px solid var(--border2);
  color: var(--text2); border-radius: 4px;
  padding: 3px 10px; cursor: pointer; transition: all 0.15s;
}
.metro-timesig-btn:hover { border-color: var(--gold); color: var(--gold2); }
.metro-timesig-btn.active {
  background: rgba(200,149,58,0.15); color: var(--gold2); border-color: var(--gold);
}

/* ── Chord Detector ── */
.detect-status {
  display: flex; align-items: center; gap: 12px;
  margin-bottom: 24px; flex-wrap: wrap;
}

.detect-btn {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px; font-weight: 600;
  cursor: pointer; border-radius: 6px;
  padding: 10px 22px; border: 1px solid var(--border2);
  transition: all 0.15s; background: none; color: var(--text2);
}
.detect-btn:hover { border-color: var(--gold); color: var(--gold2); }
.detect-btn.listening {
  background: rgba(80,200,160,0.12);
  border-color: #50c890; color: #50c890;
}

.detect-source-badge {
  font-size: 10px; font-weight: 600;
  font-family: 'IBM Plex Mono', monospace;
  padding: 2px 8px; border-radius: 10px;
  background: rgba(200,149,58,0.12); color: var(--gold2);
}
.detect-source-badge.midi { background: rgba(80,200,160,0.12); color: #50c890; }

.detect-result {
  display: flex; flex-wrap: wrap; gap: 24px;
  align-items: flex-start; margin-bottom: 20px;
}

.detect-chord-name {
  font-family: 'Playfair Display', serif;
  font-size: 52px; font-weight: 900;
  color: var(--gold2); line-height: 1;
  min-height: 60px;
}
.detect-chord-type {
  font-size: 12px; color: var(--text3);
  font-family: 'IBM Plex Mono', monospace;
  margin-top: 4px;
}
.detect-alts {
  display: flex; flex-direction: column; gap: 4px; justify-content: flex-end;
  padding-bottom: 6px;
}
.detect-alt {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px; color: var(--text3);
}

.detect-notes {
  display: flex; flex-wrap: wrap; gap: 6px;
  margin-bottom: 20px; min-height: 28px;
}
.detect-note-pill {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px; font-weight: 600;
  padding: 3px 10px; border-radius: 6px;
  background: rgba(155,126,212,0.15); color: #9b7ed4;
  border: 1px solid rgba(155,126,212,0.3);
}

.detect-piano-wrap { overflow-x: auto; -webkit-overflow-scrolling: touch; }

.detect-error {
  background: rgba(180,40,40,0.12);
  border: 1px solid rgba(180,40,40,0.3);
  border-radius: 6px; padding: 12px 16px;
  font-size: 13px; color: #e07060;
  font-family: 'IBM Plex Mono', monospace;
  margin-bottom: 16px; display: none;
}

.detect-midi-note {
  font-size: 11px; color: #50c890;
  font-family: 'IBM Plex Mono', monospace;
  margin-top: 6px;
}

/* ── Mobile responsive ── */
@media (max-width: 600px) {
  .practice-page { padding: 0 12px 100px; }
  .practice-section { padding: 20px 0 24px; }
  .practice-section-title { font-size: 22px; }
  .metro-bpm-display { font-size: 56px; }
  .detect-chord-name { font-size: 40px; }
}