:root {
  --bg-color: #0f1117;
  --panel-bg: #181b24;
  --card-bg: #1f2330;
  --border-color: #2e3446;
  --accent-color: #6366f1;
  --accent-hover: #4f46e5;
  --root-color: #ef4444;
  --root-hover: #dc2626;
  --scale-note-bg: #3b82f6;
  --scale-note-text: #ffffff;
  --text-main: #f3f4f6;
  --text-muted: #9ca3af;
  --text-dim: #6b7280;
  --wood-bg: #1c1815;
  --fret-wire: #8892b0;
  --fret-marker: #4b5563;
  --string-color: #94a3b8;
  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
}

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

body {
  background-color: var(--bg-color);
  color: var(--text-main);
  font-family: var(--font-sans);
  line-height: 1.5;
  padding-bottom: 40px;
}

.app-header {
  background-color: var(--panel-bg);
  border-bottom: 1px solid var(--border-color);
  padding: 20px 40px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 15px;
  width: 100%;
}

.logo-container {
  display: flex;
  align-items: center;
  gap: 15px;
}

.logo-icon {
  font-size: 2.2rem;
}

.app-header h1 {
  font-size: 1.5rem;
  font-weight: 700;
  color: #fff;
}

.subtitle {
  color: var(--text-muted);
  font-size: 0.875rem;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 18px;
}

.header-nav a {
  color: #a5b4fc;
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 600;
  transition: color 0.2s;
}

.header-nav a:hover {
  color: #fff;
}

/* ADSENSE CONTAINERS */
.adsense-container {
  width: 100%;
  max-width: 1500px;
  margin: 15px auto;
  padding: 10px 20px;
  background-color: rgba(31, 35, 48, 0.4);
  border: 1px dashed var(--border-color);
  border-radius: 8px;
  text-align: center;
  min-height: 90px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  position: relative;
}

.adsense-placeholder-label {
  font-size: 0.72rem;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 4px;
}

.app-container {
  width: 100%;
  max-width: 1500px;
  margin: 15px auto;
  padding: 0 20px;
  display: flex;
  flex-direction: column;
  gap: 35px;
}

/* Cards & Containers */
.card {
  background-color: var(--panel-bg);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 26px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

/* THEORY FORMULA GUIDE BOX */
.theory-guide-box {
  border-left: 4px solid var(--accent-color);
}

.theory-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 16px;
  margin-top: 10px;
}

.th-col {
  background-color: var(--panel-bg);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 14px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.th-col h5 {
  color: #a5b4fc;
  font-size: 0.95rem;
}

.th-col p {
  font-size: 0.88rem;
  color: #d1d5db;
  line-height: 1.5;
}

/* FULL-WIDTH ENCICLOPEDIA & WIDE SLABS */
.wiki-section {
  display: flex;
  flex-direction: column;
  gap: 25px;
  width: 100%;
}

.wiki-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 16px;
  gap: 15px;
}

.wiki-header h2 {
  font-size: 1.7rem;
  color: #fff;
}

.wiki-header-desc {
  color: var(--text-muted);
  font-size: 0.98rem;
  margin-top: 4px;
}

.wiki-grid {
  display: flex;
  flex-direction: column;
  gap: 28px;
  width: 100%;
}

.wiki-card {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 18px;
  width: 100%;
  box-shadow: 0 4px 12px rgba(0,0,0,0.25);
}

.wiki-card-title-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  border-bottom: 2px solid var(--border-color);
  padding-bottom: 12px;
}

.wiki-card h3 {
  font-size: 1.35rem;
  color: #a5b4fc;
  display: flex;
  align-items: center;
  gap: 10px;
}

.wiki-notes-seq-box {
  background-color: rgba(99, 102, 241, 0.12);
  border: 1px solid rgba(99, 102, 241, 0.3);
  padding: 10px 14px;
  border-radius: 8px;
  font-family: var(--font-mono);
  font-size: 0.92rem;
  color: #c7d2fe;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.wiki-notes-seq-box strong {
  color: #fbbf24;
}

.wiki-meta {
  font-family: var(--font-mono);
  font-size: 0.88rem;
  color: #fbbf24;
  background-color: rgba(245, 158, 11, 0.12);
  padding: 8px 14px;
  border-radius: 8px;
  border: 1px solid rgba(245, 158, 11, 0.25);
}

.wiki-section-detail {
  display: flex;
  flex-direction: column;
  gap: 10px;
  line-height: 1.65;
  color: #d1d5db;
  font-size: 0.96rem;
}

.wiki-section-detail h4 {
  font-size: 1.05rem;
  color: #60a5fa;
}

/* PENTATONIC & BLUE NOTE BOXES */
.pentatonic-fits-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 16px;
  margin-top: 8px;
}

.fit-box {
  background-color: var(--panel-bg);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 14px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.fit-box h5 {
  color: #f59e0b;
  font-size: 0.95rem;
}

.fit-box ul {
  padding-left: 20px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 0.9rem;
}

.blue-note-box {
  background-color: rgba(59, 130, 246, 0.1);
  border: 1px solid rgba(59, 130, 246, 0.3);
  border-radius: 8px;
  padding: 14px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.blue-note-box h5 {
  color: #60a5fa;
  font-size: 0.98rem;
}

.blue-note-box p {
  font-size: 0.9rem;
  color: #d1d5db;
  line-height: 1.5;
}

/* CONVENTIONAL REALISTIC GUITAR MINI FRETBOARD GRID COMPONENT */
.pattern-diagram-box {
  background-color: var(--panel-bg);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.pattern-diagram-box h5 {
  color: #a5b4fc;
  font-size: 0.98rem;
  font-weight: 700;
}

.mini-fretboard-grid-wrapper {
  overflow-x: auto;
  padding-bottom: 6px;
}

.mini-fretboard-grid {
  display: flex;
  flex-direction: column;
  background: var(--wood-bg);
  border: 3px solid #2d2620;
  border-radius: 6px;
  min-width: 520px;
  max-width: 850px;
  user-select: none;
}

.mini-header-row {
  display: flex;
  background-color: #12100e;
  border-bottom: 2px solid #332b23;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
}

.mini-header-str {
  width: 45px;
  padding: 6px 0;
  text-align: center;
  background-color: #0d0c0a;
  color: #a5b4fc;
  font-weight: 700;
  border-right: 2px solid #2e3446;
}

.mini-header-fret {
  flex: 1;
  text-align: center;
  padding: 6px 0;
  border-right: 1px solid rgba(255, 255, 255, 0.08);
}

.mini-header-fret:last-child {
  border-right: none;
}

.mini-grid-string-row {
  display: flex;
  position: relative;
  height: 32px;
  align-items: center;
}

.mini-grid-string-row::before {
  content: '';
  position: absolute;
  left: 45px;
  right: 0;
  top: 50%;
  height: 2px;
  background: linear-gradient(180deg, #cbd5e1, #64748b);
  z-index: 1;
  box-shadow: 0 1px 2px rgba(0,0,0,0.5);
}

.mini-string-label {
  width: 45px;
  height: 100%;
  background-color: #12100e;
  color: #f59e0b;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 0.8rem;
  display: flex;
  align-items: center;
  justify-content: center;
  border-right: 2px solid #2e3446;
  z-index: 2;
}

.mini-fret-slot {
  flex: 1;
  height: 100%;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  border-right: 2px solid var(--fret-wire);
  z-index: 2;
}

.mini-fret-slot:last-child {
  border-right: none;
}

.mini-note-badge {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.68rem;
  font-weight: 800;
  font-family: var(--font-mono);
  box-shadow: 0 2px 4px rgba(0,0,0,0.6);
  z-index: 3;
}

.mini-note-badge.badge-scale {
  background-color: var(--scale-note-bg);
  color: #ffffff;
  border: 1px solid #93c5fd;
}

.mini-note-badge.badge-root {
  background-color: var(--root-color);
  color: #ffffff;
  border: 2px solid #fca5a5;
}

.mini-note-badge.badge-blue {
  background-color: #60a5fa;
  color: #0f1117;
  border: 2px solid #93c5fd;
  box-shadow: 0 0 8px #60a5fa;
}

/* TRANSPOSED ALIGNED MODE TABLES FOR WIKI CARDS */
.wiki-modes-table-container {
  overflow-x: auto;
  background-color: var(--panel-bg);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  padding: 14px;
}

.wiki-modes-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
  text-align: left;
  min-width: 850px;
}

.wiki-modes-table th {
  background-color: var(--card-bg);
  color: #a5b4fc;
  padding: 10px 12px;
  border: 1px solid var(--border-color);
  font-weight: 700;
  text-transform: uppercase;
  font-size: 0.8rem;
}

.wiki-modes-table td {
  padding: 8px 12px;
  border: 1px solid var(--border-color);
  color: #d1d5db;
}

.wiki-modes-table .col-mode-name {
  font-weight: 700;
  color: #60a5fa;
  min-width: 170px;
}

.wiki-modes-table .col-code {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: #fbbf24;
  white-space: nowrap;
}

.wiki-modes-table .col-steps {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: #34d399;
  white-space: nowrap;
}

.wiki-modes-table .col-genre {
  font-size: 0.84rem;
  color: #c7d2fe;
  min-width: 150px;
}

.wiki-modes-table .col-desc {
  font-size: 0.85rem;
  color: #9ca3af;
  min-width: 220px;
}

/* WIDE SCROLLABLE CHORD SLABS IN WIKI CARDS */
.wiki-chords-box {
  background-color: rgba(15, 23, 42, 0.6);
  border: 1px solid rgba(99, 102, 241, 0.35);
  border-radius: 10px;
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  width: 100%;
}

.wiki-chords-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.92rem;
  font-weight: 700;
  color: #c7d2fe;
}

.scroll-hint {
  font-size: 0.78rem;
  color: #f59e0b;
  background-color: rgba(245, 158, 11, 0.15);
  padding: 3px 8px;
  border-radius: 4px;
}

.wiki-chords-scroll {
  display: flex;
  gap: 14px;
  overflow-x: auto;
  padding-bottom: 10px;
  scrollbar-width: thin;
  scrollbar-color: var(--accent-color) var(--card-bg);
}

.wiki-chords-scroll::-webkit-scrollbar {
  height: 8px;
}

.wiki-chords-scroll::-webkit-scrollbar-thumb {
  background-color: var(--accent-color);
  border-radius: 4px;
}

.chord-slab {
  flex: 0 0 auto;
  min-width: 170px;
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 12px 14px;
  display: flex;
  flex-direction: column;
  gap: 4px;
  text-align: center;
  box-shadow: 0 2px 8px rgba(0,0,0,0.3);
}

.chord-slabwide {
  flex: 0 0 auto;
  min-width: 280px;
  max-width: 320px;
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 14px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  text-align: left;
}

.c-deg {
  font-size: 0.75rem;
  font-weight: 700;
  color: #9ca3af;
  text-transform: uppercase;
}

.c-triad {
  font-family: var(--font-mono);
  font-size: 1.1rem;
  font-weight: 700;
  color: #f3f4f6;
}

.c-tetrad {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  font-weight: 600;
  color: #818cf8;
}

.c-formula {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: #34d399;
}

/* HARMONIZED CHORDS GRID (INTERACTIVE TOOL) WITH DUAL TRIAD + TETRAD ROWS */
.chords-grid-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 14px;
  width: 100%;
}

.chord-degree-card {
  background-color: var(--panel-bg);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 14px 12px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  text-align: center;
}

.chord-degree-num {
  font-family: var(--font-mono);
  font-size: 1.05rem;
  font-weight: 800;
  color: #fbbf24;
  letter-spacing: 0.5px;
}

.chord-triad-block, .chord-tetrad-block {
  display: flex;
  flex-direction: column;
  gap: 2px;
  background-color: rgba(31, 35, 48, 0.6);
  padding: 6px;
  border-radius: 6px;
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.chord-tetrad-block {
  border-color: rgba(99, 102, 241, 0.25);
  background-color: rgba(99, 102, 241, 0.08);
}

.chord-type-label {
  font-size: 0.68rem;
  font-weight: 700;
  color: #9ca3af;
  text-transform: uppercase;
}

.chord-name-main {
  font-family: var(--font-mono);
  font-size: 1.15rem;
  font-weight: 700;
  color: #f3f4f6;
}

.chord-name-tetrad {
  font-family: var(--font-mono);
  font-size: 1.05rem;
  font-weight: 700;
  color: #a5b4fc;
}

.chord-notes-span {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: #93c5fd;
}

.chord-intervals-span {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: #34d399;
}

.chord-semitones-span {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 600;
  color: #fbbf24;
  background-color: rgba(245, 158, 11, 0.12);
  padding: 2px 6px;
  border-radius: 4px;
  margin-top: 2px;
}

/* TRANSFORMATION CARDS */
.transformation-block {
  margin-top: 10px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  border-top: 1px solid var(--border-color);
  padding-top: 14px;
}

.transformation-block h5 {
  font-size: 0.95rem;
  color: #f59e0b;
}

.trans-3step-card {
  background-color: var(--panel-bg);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 14px 18px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  text-align: center;
  max-width: 480px;
}

.trans-line-base {
  font-family: var(--font-mono);
  font-size: 0.88rem;
  font-weight: 600;
  color: #93c5fd;
  background-color: rgba(59, 130, 246, 0.15);
  padding: 6px 10px;
  border-radius: 4px;
}

.trans-line-arrow {
  font-size: 0.82rem;
  font-weight: 700;
  color: #f59e0b;
  padding: 2px 0;
}

.trans-line-result {
  font-family: var(--font-mono);
  font-size: 0.88rem;
  font-weight: 700;
  color: #34d399;
  background-color: rgba(16, 185, 129, 0.15);
  padding: 6px 10px;
  border-radius: 4px;
}

/* INTERACTIVE TOOL SECTION */
.interactive-tool-section {
  display: flex;
  flex-direction: column;
  gap: 25px;
  border-top: 2px solid var(--accent-color);
  padding-top: 30px;
  width: 100%;
}

.tool-section-header h2 {
  font-size: 1.6rem;
  color: #fff;
}

.tool-section-header p {
  color: var(--text-muted);
  font-size: 0.92rem;
}

/* Control Panel */
.control-panel {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 18px;
  background-color: var(--panel-bg);
  border: 1px solid var(--border-color);
  padding: 22px;
  border-radius: 12px;
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.control-group label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.select-input {
  background-color: var(--card-bg);
  color: #fff;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 10px 12px;
  font-size: 0.95rem;
  font-family: var(--font-sans);
  outline: none;
  cursor: pointer;
  transition: border-color 0.2s;
}

.select-input:focus, .select-input:hover {
  border-color: var(--accent-color);
}

/* UNIFIED FRETBOARD & TUNING CARD */
.fretboard-unified-card {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.tuning-integrated-block {
  border-top: 1px solid var(--border-color);
  padding-top: 16px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.tuning-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
}

.tuning-header h4 {
  font-size: 1.05rem;
  color: #fff;
}

.tuning-presets {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.tuning-inputs {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.tuning-string-item {
  display: flex;
  align-items: center;
  gap: 6px;
  background-color: var(--card-bg);
  padding: 6px 12px;
  border-radius: 8px;
  border: 1px solid var(--border-color);
  font-size: 0.85rem;
}

.tuning-select {
  background-color: var(--bg-color);
  color: #fff;
  border: 1px solid var(--border-color);
  border-radius: 4px;
  padding: 4px 6px;
  font-family: var(--font-mono);
}

/* Scale Info Panel & Formula Text */
.scale-info-panel {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.scale-title-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 15px;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 15px;
}

.scale-title-row h2 {
  font-size: 1.6rem;
  font-weight: 700;
  color: #fff;
  display: flex;
  align-items: center;
  gap: 10px;
}

.badge {
  background-color: var(--accent-color);
  color: #fff;
  font-size: 0.75rem;
  padding: 4px 10px;
  border-radius: 20px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.playback-controls {
  display: flex;
  align-items: center;
  gap: 15px;
}

.speed-label {
  font-size: 0.85rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 8px;
}

.scale-details-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 15px;
}

.detail-card {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 14px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.detail-full {
  grid-column: 1 / -1;
}

.detail-label {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
}

/* FORMULA DIRECT TEXT DISPLAY */
.formula-text-container {
  display: flex;
  flex-direction: column;
  gap: 4px;
  background-color: var(--panel-bg);
  padding: 10px 14px;
  border-radius: 6px;
  border: 1px solid var(--border-color);
}

.formula-line-text {
  font-family: var(--font-mono);
  font-size: 1.05rem;
  font-weight: 700;
  color: #60a5fa;
  letter-spacing: 0.5px;
}

.formula-chips, .notes-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.chip {
  background-color: var(--panel-bg);
  border: 1px solid var(--border-color);
  padding: 4px 10px;
  border-radius: 6px;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  font-weight: 600;
}

.chip.chip-root {
  background-color: var(--root-color);
  border-color: var(--root-hover);
  color: #fff;
}

.description-text {
  color: #d1d5db;
  font-size: 0.95rem;
  line-height: 1.6;
}

/* FRETBOARD STYLING AND PHYSICAL NUT BETWEEN FRET 0 AND FRET 1 */
.fretboard-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
}

.fretboard-legend {
  display: flex;
  gap: 15px;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 6px;
}

.legend-color {
  width: 12px;
  height: 12px;
  border-radius: 50%;
}

.root-color {
  background-color: var(--root-color);
}

.scale-color {
  background-color: var(--scale-note-bg);
}

.fretboard-scroll-wrapper {
  overflow-x: auto;
  padding-bottom: 10px;
  border-radius: 8px;
}

.fretboard {
  display: flex;
  flex-direction: column;
  background: var(--wood-bg);
  border: 3px solid #2d2620;
  border-radius: 6px;
  min-width: 1250px;
  position: relative;
  user-select: none;
}

.fret-numbers-row {
  display: grid;
  grid-template-columns: 80px 55px repeat(24, minmax(42px, 1fr));
  background-color: #12100e;
  border-bottom: 2px solid #332b23;
}

.fret-number-cell {
  text-align: center;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  padding: 6px 0;
  border-right: 1px solid rgba(255, 255, 255, 0.05);
}

.fret-number-cell.fret-open-header {
  color: #60a5fa;
  font-weight: 700;
  border-right: 6px solid #e5e7eb;
}

.fret-number-cell.has-marker {
  color: #f59e0b;
  font-weight: 700;
}

.fret-string-row {
  display: grid;
  grid-template-columns: 80px 55px repeat(24, minmax(42px, 1fr));
  position: relative;
  height: 38px;
  align-items: center;
}

.fret-string-row::before {
  content: '';
  position: absolute;
  left: 80px;
  right: 0;
  top: 50%;
  height: var(--string-thickness, 2px);
  background: linear-gradient(180deg, #cbd5e1, #64748b);
  z-index: 1;
  box-shadow: 0 1px 3px rgba(0,0,0,0.6);
}

.string-label-cell {
  background-color: #12100e;
  color: #fff;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 0.85rem;
  display: flex;
  align-items: center;
  justify-content: center;
  border-right: 2px solid #2e3446;
  z-index: 2;
  height: 100%;
}

.fret-note-cell {
  position: relative;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  border-right: 2px solid var(--fret-wire);
  z-index: 2;
  cursor: pointer;
}

.fret-note-cell.fret-open-cell {
  background-color: rgba(255, 255, 255, 0.03);
  border-right: 6px solid #e5e7eb;
}

.fret-note-cell.fret-open-cell:hover {
  background-color: rgba(99, 102, 241, 0.2);
}

.open-string-text-label {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 700;
  color: #93c5fd;
  z-index: 3;
}

.open-string-text-label.is-root {
  color: #fca5a5;
  font-weight: 900;
}

.fret-note-cell:hover {
  background-color: rgba(255, 255, 255, 0.08);
}

.fret-marker-single, .fret-marker-double {
  position: absolute;
  background-color: var(--fret-marker);
  border-radius: 50%;
  opacity: 0.35;
  z-index: 1;
  pointer-events: none;
}

.fret-marker-single {
  width: 12px;
  height: 12px;
}

.fret-marker-double {
  width: 10px;
  height: 10px;
}

.fret-note-badge {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.72rem;
  font-weight: 700;
  font-family: var(--font-mono);
  box-shadow: 0 2px 5px rgba(0,0,0,0.5);
  transition: transform 0.15s ease, box-shadow 0.15s ease;
  z-index: 3;
}

.fret-note-badge:hover {
  transform: scale(1.25);
  box-shadow: 0 0 10px rgba(255, 255, 255, 0.8);
}

.fret-note-badge.note-root {
  background-color: var(--root-color);
  color: #fff;
  border: 2px solid #fca5a5;
}

.fret-note-badge.note-scale {
  background-color: var(--scale-note-bg);
  color: var(--scale-note-text);
  border: 1px solid #93c5fd;
}

.fret-note-badge.playing {
  transform: scale(1.4);
  background-color: #10b981 !important;
  border-color: #6ee7b7 !important;
  color: #fff !important;
  box-shadow: 0 0 14px #10b981;
}

/* Relativity Matrix Table */
.matrix-section {
  display: flex;
  flex-direction: column;
  gap: 15px;
}

.matrix-subtitle {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.table-scroll-wrapper {
  overflow-x: auto;
}

.relativity-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
  text-align: left;
}

.relativity-table th {
  background-color: var(--card-bg);
  color: #fff;
  padding: 12px 14px;
  border: 1px solid var(--border-color);
  font-weight: 600;
}

.relativity-table td {
  padding: 10px 14px;
  border: 1px solid var(--border-color);
  font-family: var(--font-mono);
  color: #d1d5db;
}

.relativity-table tr:nth-child(even) {
  background-color: rgba(255, 255, 255, 0.02);
}

.relativity-table tr:hover {
  background-color: rgba(99, 102, 241, 0.1);
}

.relativity-table td.highlight-root {
  background-color: rgba(239, 68, 68, 0.25);
  color: #fff;
  font-weight: 700;
}

/* Buttons */
.btn {
  padding: 8px 16px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  border: none;
  transition: background-color 0.2s, transform 0.1s;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
}

.btn:active {
  transform: scale(0.97);
}

.btn-primary {
  background-color: var(--accent-color);
  color: #fff;
}

.btn-primary:hover {
  background-color: var(--accent-hover);
}

.btn-sm {
  padding: 4px 10px;
  font-size: 0.78rem;
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  color: #d1d5db;
}

.btn-sm:hover {
  background-color: var(--border-color);
}

.app-footer {
  text-align: center;
  padding: 25px 20px;
  color: var(--text-dim);
  font-size: 0.85rem;
  display: flex;
  flex-direction: column;
  gap: 10px;
  background-color: var(--panel-bg);
  border-top: 1px solid var(--border-color);
  margin-top: 30px;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 15px;
  flex-wrap: wrap;
}

.footer-links a {
  color: #9ca3af;
  text-decoration: none;
  transition: color 0.2s;
}

.footer-links a:hover {
  color: #a5b4fc;
}

/* MOBILE ADAPTATION & RESPONSIVENESS */
@media (max-width: 768px) {
  .app-header {
    padding: 12px 15px;
  }
  .app-container {
    padding: 0 8px;
    margin: 10px auto;
    gap: 20px;
  }
  .adsense-container {
    padding: 8px 10px;
    margin: 10px auto;
  }
  .card {
    padding: 14px;
    border-radius: 10px;
  }
  .wiki-card {
    padding: 14px;
    border-radius: 10px;
  }
  .wiki-chords-box {
    padding: 12px;
  }
  .chord-slab {
    min-width: 145px;
    padding: 10px;
  }
  .chord-slabwide {
    min-width: 230px;
    padding: 12px;
  }
  .chords-grid-container {
    grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
    gap: 8px;
  }
  .chord-degree-card {
    padding: 8px;
  }
  .pentatonic-fits-grid {
    grid-template-columns: 1fr;
  }
  .trans-3step-card {
    max-width: 100%;
  }
  .control-panel {
    grid-template-columns: 1fr;
    padding: 14px;
  }
}

@media (max-width: 480px) {
  .app-container {
    padding: 0 4px;
  }
  .card {
    padding: 12px 10px;
  }
  .wiki-card {
    padding: 12px 10px;
  }
  .wiki-header h2 {
    font-size: 1.3rem;
  }
  .wiki-card h3 {
    font-size: 1.15rem;
  }
  .chords-grid-container {
    grid-template-columns: 1fr 1fr;
  }
}