:root{
  --bg-1: #0b0f14;          /* page background */
  --bg-2: #0f1720;          /* secondary background (slightly lighter) */
  --card-bg: rgba(255,255,255,0.03);
  --card-border: rgba(255,255,255,0.06);
  --glass-blur: 10px;

  --text: #e6eef3;
  --muted: #97a6af;
  --accent: #00e5ff;        /* cyan accent for highlights */
  --accent-2: #ffb86b;      /* warm accent (used sparingly) */
  --accent-3: #027f8d;        /* cyan accent for highlights */
  --interactive-bg: rgba(255,255,255,0.04);
  --chip-bg: rgba(0,0,0,0.45);
  --danger: #ff6b6b;
  --shadow: rgba(2,6,23,0.7);
}

/* reset */
*{
  margin:0;
  padding:0;
  box-sizing:border-box;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
}

body{
  font-family: 'Inter', 'Segoe UI', Roboto, Arial, sans-serif;
  background: linear-gradient(135deg, var(--bg-1) 0%, #071016 100%);
  color: var(--text);
  padding: 24px;
	padding-top: 5px;
	padding-bottom: 5px;
  overflow-x: hidden;
  line-height:1.45;
  -webkit-tap-highlight-color: transparent;
}

/* central container */
.container{
  max-width: calc(100% - 50px);
  margin: 0 auto;
}

/* heading */
h1{
  text-align:center;
  font-size:2.4em;
  margin-bottom:8px;
  color: var(--text);
  letter-spacing: -0.02em;
  text-shadow: 0 6px 18px rgba(0,0,0,0.6);
}

.subtitle{
  text-align:center;
  font-size:1.02em;
  margin-bottom:26px;
  color:var(--muted);
}

/* tab nav */
.tab-nav{
  display:flex;
  justify-content:center;
  gap:10px;
  margin-bottom:26px;
  flex-wrap:wrap;
}

.tab-btn{
  padding:10px 18px;
  background: transparent;
  border: 1px solid var(--card-border);
  color: var(--muted);
  cursor: pointer;
  border-radius:10px;
  font-size:0.98em;
  transition: all 220ms cubic-bezier(.2,.9,.32,1);
  backdrop-filter: blur(6px);
  box-shadow: 0 4px 14px rgba(2,6,23,0.45);
}

.tab-btn:hover{
  transform: translateY(-3px);
  color: var(--text);
  border-color: rgba(0,230,255,0.12);
  background: linear-gradient(180deg, rgba(255,255,255,0.01), rgba(255,255,255,0.02));
}

.tab-btn.active{
  background: linear-gradient(90deg, rgba(0,230,255,0.12), rgba(255,184,107,0.08));
  border: 1px solid rgba(0,230,255,0.22);
  box-shadow: 0 8px 30px rgba(0,230,255,0.06);
}

.tab-btn:focus, .tab-btn:active{
  outline: none;
  box-shadow: 0 0 0 4px rgba(0,230,255,0.06);
  border-color: rgba(0, 0, 0, 0.18);
}


/* tabs content */
.tab-content{
  display:none;
  animation: fadeIn 420ms ease both;
}

.tab-content.active{
  display:block;
}

@keyframes fadeIn{
  from{ opacity:0; transform: translateY(8px); }
  to{ opacity:1; transform: translateY(0); }
}

/* grids */
.grid{
  display:grid;
  gap:20px;
  margin-bottom:20px;
}

.grid-2 { grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); }
.grid-3 {
  grid-template-areas:
		"a b d"
		"a c c";
}
.grid-4 {
  position: relative;
	grid-template-areas:
		"a a d"
		"c b d";
}
.grid-5 {
	grid-template-areas:
		"a b"
		"a c";
}
.grid-6 {
	grid-template-areas:
		"a c"
		"b d";
}
.grid-7 {
	grid-template-areas:
		"a b c"
		"a b d";
}

/* card (glass) */
.card{
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius:14px;
  padding:20px;
  backdrop-filter: blur(var(--glass-blur));
  transition: transform 260ms cubic-bezier(.2,.9,.32,1), box-shadow 260ms;
  box-shadow: 0 6px 30px var(--shadow);
}

.card:hover{
  transform: translateY(-1px);
  box-shadow: 0 18px 50px rgba(0,0,0,0.6);
  border-color: rgba(0,230,255,0.06);
}

.card-circle {
	width: auto;
	height: min-content;
}

/* headings inside cards */
.card h3{
  font-size:1.28em;
  margin-bottom:12px;
  color: var(--accent-2);
}

.card h4{
  font-size:1.03em;
  margin-top:12px;
  margin-bottom:8px;
  color: var(--accent);
}

/* lists */
.card-fund .scale-formula li {
  font-size: 1.25em;
}

.interval-list, .chord-formula, .scale-formula{
  list-style:none;
  padding:10px 0;
}

.interval-list li, .chord-formula li, .scale-formula li{
  padding:10px;
  margin:8px 0;
  background: rgba(255,255,255,0.02);
  border-radius:8px;
  border-left: 4px solid rgba(0,230,255,0.12);
  color: var(--text);
  font-size:0.96em;
	cursor: default;
}

.interval-list li:hover span, .scale-formula li:hover {
	color: var(--accent-2);
	border-color: rgba(0,230,255,0.12);
	cursor: pointer;
}

.interval-list li {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 12px;
}

.interval-list-2, .chord-formula, .scale-formula{
  list-style:none;
  padding:10px 0;
}

.interval-list-2 li, .chord-formula li, .scale-formula li{
  padding:10px;
  margin:8px 0;
  background: rgba(255,255,255,0.02);
  border-radius:8px;
  border-left: 4px solid rgba(0,230,255,0.12);
  color: var(--text);
  font-size:0.96em;
	cursor: default;
}

.interval-list-2 li:hover span, .scale-formula li:hover {
	color: var(--accent-2);
	border-color: rgba(0,230,255,0.12);
	cursor: pointer;
}

.interval-name {
  font-weight: bold;
  text-align: right;
}

/* fretboard (darker wood replaced with charcoal) */
.fretboard{
  background: linear-gradient(180deg, #0f1418, #0b1013);
  border: 1px solid rgba(255,255,255,0.04);
  border-radius:10px;
  padding:18px;
  margin:18px 0;
  overflow-x:auto;
}

.fret-grid{
  display:grid;
  grid-template-columns: repeat(13, 1fr);
  gap:6px;
  min-width:600px;
}

.fret-cell{
  aspect-ratio: 1;
  border-radius:6px;
  border: 1px solid rgba(255,255,255,0.03);
  display:flex;
  align-items:center;
  justify-content:center;
  font-size:0.9em;
  font-weight:600;
  background: linear-gradient(180deg, rgba(255,255,255,0.01), rgba(255,255,255,0.0));
}

/* fret marker */
.fret-marker{
  background: rgba(255,184,107,0.08);
  border-radius:50%;
}

/* progression / small UI chips */
.progression-box{
  display:flex;
  gap:10px;
  flex-wrap:wrap;
  margin:10px 0;
}

.blues {
	display: grid;
	grid-template-columns: repeat(4, 1fr);
	gap: 10px;
	margin: 10px 0;
}

.chord-box{
  background: rgba(255,255,255,0.03);
  padding:10px 14px;
  border-radius:10px;
  font-weight:700;
  font-size:1.05em;
  color: var(--text);
  border: 1px solid rgba(255,255,255,0.03);
  box-shadow: 0 6px 18px rgba(0,0,0,0.45);
}

/* note circle: modern neon rim */
.note-circle{
  display:inline-flex;
  width:44px;
  height:44px;
  border-radius:50%;
  background: linear-gradient(180deg, rgba(255,255,255,0.01), rgba(255,255,255,0.015));
  border: 1px solid rgba(255,255,255,0.04);
  align-items:center;
  justify-content:center;
  margin:6px;
  font-weight:700;
  color: var(--text);
  box-shadow: 0 6px 18px rgba(0,0,0,0.6), inset 0 1px 0 rgba(255,255,255,0.02);
	cursor: pointer;
}

.note-circle:hover{
	color: var(--accent-2);
	border-color: rgba(0,230,255,0.12);
	background: linear-gradient(180deg, rgba(255,255,255,0.01), rgba(255,255,255,0.02));
}

.notes-circles {
  font-size: 2em;
  text-align: center;
  margin: 2px 0;
  cursor: default;
}

.shell {
  display: grid;
  grid-template-areas:
    "a"
    "b";
}

.shells {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  grid-template-rows: repeat(2, 1fr);
}

/* shell voicing cards */
.shell-voicing{
  background: var(--chip-bg);
  padding:10px;
  border-radius:10px;
  margin:10px 0;
  border: 1px solid rgba(255,255,255,0.03);
  max-height: 200px;
  max-width: 200px;
  position: relative;
}

.shell-voicing h4 {
  font-size: 1em;
  margin: 0;
}

/* string diagram */
.string-diagram { display:flex; flex-direction:column; gap:0px; margin:10px 0; }

.string { display:flex; align-items:center; gap:1px; }

.string-label{
  width:15px;
  font-weight:500;
  color:var(--muted);
}

/* string line */
.string-line {
  flex: 1;
  height: 2px;
  border-radius: 2px;
  position: relative;
  background: repeating-linear-gradient(
    90deg,
    rgba(255, 255, 255, 0.8) 0,          /* bright fret edge */
    rgba(255, 255, 255, 0.8) 2px,        /* fret width */
    rgba(255, 255, 255, 0.15) 2px,       /* start of string area */
    rgba(255, 255, 255, 0.15) calc(100% * 4)  /* divide into 12 equal segments */
  );
  background-size: calc(100% / 4) 100%;
  background-repeat: repeat-x;
  /* box-shadow: 0 1px 2px rgba(0, 0, 0, 0.6); adds subtle depth */
}

/* note markers (use accent and softer border) */
.note-marker{
  transform: translateY(-50%);
  position:absolute;
  width:22px;
  height:22px;
  background: linear-gradient(180deg, var(--accent), rgba(0,200,220,0.85));
  border-radius:50%;
  border: 1px solid rgba(255,255,255,0.9);
  display:flex;
  align-items:center;
  justify-content:center;
  font-size:0.72em;
  color:#02262b;
  font-weight:800;
  box-shadow: 0 8px 20px rgba(0,0,0,0.6);
}

/* smaller UI tweaks */
.card p{ color: var(--muted); font-size:0.96em; }
.card strong{ color: var(--text); }

/* svg circle of fifths overrides (force dark theme colors) */
.circle-svg text{
  fill: var(--accent-2) !important;
  font-weight:700;
}

.circle-svg text[font-size="23"]:nth-child(odd), .circle-svg text[font-size="16"]:nth-child(even){
  fill: var(--accent) !important;
}

/* small text badges (sharps/flats) */
.circle-svg text[font-size="14"]{
  fill: var(--danger) !important;
  font-weight:600;
}

.circle-of-fifths {
	display: flex;
	justify-content: center;
	align-items: center;
	margin: 0px 0;
}

.circle-svg {
	max-width: 600px;
	width: 100%;
	height: auto;
}

/* responsive tweaks */
@media (max-width:600px){
  h1{ font-size:1.6em; }
  .tab-btn{ padding:8px 12px; font-size:0.9em; }
  .note-circle{ width:36px; height:36px; }
}

line {
	stroke: rgba(255, 255, 255, 0.03);
	stroke-width: 2;
}

.chords-li-example {
  display: grid;
  gap: 8px;
  justify-items: center;
}