.tonnetz-learn {
  --learn-cyan: var(--cyan, #64e5df);
  --learn-gold: var(--gold, #ffc65a);
  --learn-violet: #c99cff;
  --learn-bg: rgba(9, 28, 36, 0.72);
  --learn-border: var(--panel-border, rgba(175, 222, 231, 0.16));
  --learn-text: var(--text, #edf8f6);
  --learn-muted: var(--muted, #90adb0);
  width: 100%;
  min-width: 0;
  padding: 4px clamp(10px, 3vw, 16px) 28px;
  color: var(--learn-text);
  font-family: inherit;
  touch-action: pan-x pan-y;
}

.tonnetz-learn *,
.tonnetz-learn *::before,
.tonnetz-learn *::after {
  box-sizing: border-box;
}

.learn-header {
  padding: 8px 2px 14px;
}

.learn-header h2,
.learn-card h3 {
  margin: 0;
  color: var(--learn-text);
  line-height: 1.16;
  text-wrap: balance;
}

.learn-header h2 {
  font-size: clamp(1.34rem, 4.5vw, 1.72rem);
  letter-spacing: -0.025em;
}

.learn-header p,
.learn-card p {
  margin: 8px 0 0;
  color: var(--learn-muted);
  font-size: 0.88rem;
  line-height: 1.55;
}

.learn-header .learn-eyebrow {
  margin: 0 0 7px;
  color: var(--learn-cyan);
  font-size: 0.875rem;
  font-weight: 750;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.learn-stage-tabs {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 7px;
  margin-bottom: 10px;
}

.learn-stage-tab,
.learn-action-button,
.learn-chord-choice,
.learn-icon-button,
.learn-reset-button,
.learn-play-chord {
  min-height: 44px;
  border: 1px solid var(--learn-border);
  border-radius: 11px;
  color: var(--learn-text);
  background: rgba(18, 43, 52, 0.84);
  cursor: pointer;
}

.learn-stage-tab {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 7px 9px;
  text-align: left;
  font-size: 1rem;
  font-weight: 680;
  line-height: 1.15;
}

.learn-stage-tab span {
  flex: 0 0 25px;
  height: 25px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  color: var(--learn-muted);
  background: rgba(255, 255, 255, 0.06);
}

.learn-stage-tab.is-active {
  border-color: rgba(100, 229, 223, 0.58);
  color: #fff;
  background: rgba(32, 105, 111, 0.38);
  box-shadow: inset 0 0 0 1px rgba(100, 229, 223, 0.12);
}

.learn-stage-tab.is-active span {
  color: #062026;
  background: var(--learn-cyan);
}

.learn-card {
  margin: 0 0 12px;
  padding: 14px;
  overflow: hidden;
  border: 1px solid var(--learn-border);
  border-radius: 16px;
  background: linear-gradient(145deg, rgba(17, 42, 51, 0.82), var(--learn-bg));
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.13);
}

.learn-card h3 {
  font-size: 1rem;
}

.learn-axis-copy {
  color: var(--learn-cyan) !important;
  font-size: 0.875rem !important;
  font-weight: 700;
}

.learn-diagram-scroll {
  position: relative;
  width: calc(100% + 8px);
  margin: 12px -4px 0;
  padding: 2px 4px 7px;
  overflow-x: auto;
  overflow-y: hidden;
  border-radius: 12px;
  scrollbar-width: thin;
  scrollbar-color: rgba(100, 229, 223, 0.4) transparent;
  touch-action: pan-x pan-y;
  -webkit-overflow-scrolling: touch;
}

.learn-diagram-scroll:focus-visible {
  outline: 2px solid var(--learn-cyan);
  outline-offset: 2px;
}

.learn-diagram-scroll svg {
  display: block;
  width: 640px;
  min-width: 610px;
  height: auto;
  margin-inline: auto;
  border-radius: 11px;
  background:
    radial-gradient(circle at 50% 40%, rgba(100, 229, 223, 0.07), transparent 55%),
    rgba(2, 14, 20, 0.42);
}

.learn-diagram-scroll .learn-cell.is-period { width: 680px; }
.learn-diagram-scroll .learn-ring { width: 400px; min-width: 320px; max-width: 100%; }
.learn-diagram-scroll .learn-chord-grid { width: 720px; }
.learn-diagram-scroll .learn-edge-legend { width: 680px; }
.learn-diagram-scroll .learn-cell.is-expanded { width: 860px; }

.learn-scroll-hint {
  display: block;
  width: max-content;
  margin: 5px auto 0;
  color: var(--learn-muted);
  font-size: 0.875rem;
}

@media (min-width: 680px) {
  .learn-scroll-hint { display: none; }
}

.learn-ring text,
.learn-cell text,
.learn-chord-grid text,
.learn-edge-legend text {
  fill: var(--learn-text);
  font-family: inherit;
  font-weight: 720;
  text-anchor: middle;
  pointer-events: none;
  paint-order: stroke;
  stroke: rgba(4, 18, 23, 0.9);
  stroke-width: 2.5px;
}

.learn-ring text { font-size: 18px; }

.learn-chromatic-edge {
  stroke: rgba(151, 185, 190, 0.34);
  stroke-width: 2;
}

.learn-fifth-edge {
  stroke: var(--learn-gold);
  stroke-width: 2.5;
  opacity: 0.82;
}

#learn-arrow path { fill: var(--learn-gold); }

.learn-note circle {
  fill: #112d36;
  stroke: rgba(173, 220, 224, 0.56);
  stroke-width: 1.8;
}

.learn-note,
.learn-cell-note,
.learn-grid-note,
.learn-edge-sample {
  cursor: pointer;
  outline: none;
}

.learn-note:hover circle,
.learn-note:focus-visible circle,
.learn-cell-note:hover path,
.learn-cell-note:focus-visible path,
.learn-grid-note:hover path,
.learn-grid-note:focus-visible path {
  fill: rgba(100, 229, 223, 0.3);
  stroke: var(--learn-cyan);
  stroke-width: 3;
}

.learn-grid-edge {
  stroke-width: 1.5;
  opacity: 0.42;
}

.learn-grid-edge.fifth { stroke: var(--learn-gold); }
.learn-grid-edge.major-third { stroke: var(--learn-cyan); }
.learn-grid-edge.minor-third { stroke: var(--learn-violet); }

.learn-cell-note path,
.learn-grid-note path {
  fill: #102a32;
  stroke: rgba(168, 206, 211, 0.4);
  stroke-width: 1.25;
}

.learn-cell-note text,
.learn-grid-note text { font-size: 16px; }
.learn-cell-note.is-copy { opacity: 0.83; }
.learn-cell-note.is-origin path { fill: rgba(29, 78, 84, 0.92); }

.learn-cell.is-expanded {
  min-width: 860px;
}

.learn-period-boundary {
  stroke-width: 2;
  vector-effect: non-scaling-stroke;
}

.learn-period-boundary.tone-0 { fill: rgba(100, 229, 223, 0.045); stroke: rgba(100, 229, 223, 0.28); }
.learn-period-boundary.tone-1 { fill: rgba(255, 198, 90, 0.045); stroke: rgba(255, 198, 90, 0.26); }
.learn-period-boundary.tone-2 { fill: rgba(201, 156, 255, 0.045); stroke: rgba(201, 156, 255, 0.26); }
.learn-period-boundary.tone-3 { fill: rgba(121, 214, 255, 0.045); stroke: rgba(121, 214, 255, 0.26); }

.learn-cell-note.is-plane.tone-0 path { fill: #123238; }
.learn-cell-note.is-plane.tone-1 path { fill: #352d1e; }
.learn-cell-note.is-plane.tone-2 path { fill: #2d263b; }
.learn-cell-note.is-plane.tone-3 path { fill: #1c303d; }

.learn-formulas {
  display: grid;
  gap: 7px;
  margin: 13px 0;
}

.learn-formula {
  min-height: 36px;
  display: flex;
  align-items: center;
  width: 100%;
  padding: 5px 10px;
  overflow-x: auto;
  border: 1px solid rgba(175, 222, 231, 0.1);
  border-radius: 9px;
  color: #f4fbfa;
  background: rgba(2, 14, 20, 0.42);
  font-family: "STIX Two Math", "Cambria Math", serif;
  font-size: 1rem;
}

.learn-formula .katex { font-size: 1.02em; }

.learn-button-row,
.learn-move-row {
  display: flex;
  gap: 8px;
}

.learn-action-button {
  flex: 1;
  padding: 8px 11px;
  color: var(--learn-cyan);
  font-size: 1rem;
  font-weight: 720;
}

.learn-action-button.is-pure { color: var(--learn-gold); }

.learn-edge-legend { min-width: 680px !important; }
.learn-edge-sample text { font-size: 16px; text-anchor: start; }
.learn-edge-sample line { stroke-width: 4; }
.learn-edge-sample circle { fill: #102a32; stroke-width: 3; }
.learn-edge-sample.fifth line,
.learn-edge-sample.fifth circle { stroke: var(--learn-gold); }
.learn-edge-sample.major-third line,
.learn-edge-sample.major-third circle { stroke: var(--learn-cyan); }
.learn-edge-sample.minor-third line,
.learn-edge-sample.minor-third circle { stroke: var(--learn-violet); }
.learn-edge-sample:hover { filter: brightness(1.3); }
.learn-edge-sample:focus-visible circle { fill: rgba(255, 255, 255, 0.2); }

.learn-chord-picker {
  display: flex;
  gap: 7px;
  margin: 12px 0 10px;
  padding-bottom: 3px;
  overflow-x: auto;
  scrollbar-width: thin;
  touch-action: pan-x pan-y;
}

.learn-chord-choice {
  flex: 0 0 auto;
  min-width: 64px;
  padding: 8px 10px;
  font-size: 1rem;
  font-weight: 740;
}

.learn-chord-choice.is-active {
  border-color: var(--learn-gold);
  color: #211506;
  background: var(--learn-gold);
}

.learn-move-row { justify-content: space-between; }

.learn-icon-button,
.learn-reset-button {
  min-width: 88px;
  padding: 7px 10px;
  color: var(--learn-cyan);
  font-size: 1rem;
  font-weight: 700;
}

.learn-icon-button:disabled {
  cursor: default;
  opacity: 0.34;
}

.learn-reset-button {
  min-width: 0;
  color: var(--learn-muted);
}

.learn-current-chord {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 2px 9px;
  align-items: center;
  margin-top: 10px;
  padding: 10px;
  border-radius: 11px;
  background: rgba(2, 14, 20, 0.45);
}

.learn-current-chord strong {
  grid-row: 1 / 3;
  min-width: 55px;
  color: var(--learn-gold);
  font-size: 1.1rem;
}

.learn-current-chord span {
  color: var(--learn-muted);
  font-size: 0.875rem;
  line-height: 1.35;
}

.learn-play-chord {
  min-height: 38px;
  grid-column: 2;
  padding: 5px 10px;
  color: var(--learn-cyan);
  font-size: 1rem;
  font-weight: 750;
}

.learn-chord-polygon {
  fill: rgba(255, 198, 90, 0.17);
  stroke: var(--learn-gold);
  stroke-width: 8;
  stroke-linejoin: round;
  opacity: 0.9;
  pointer-events: none;
}

.learn-chord-polygon.minor { fill: rgba(201, 156, 255, 0.18); stroke: var(--learn-violet); }
.learn-chord-polygon.augmented { fill: rgba(255, 144, 103, 0.19); stroke: #ff9067; }
.learn-chord-polygon.diminished { fill: rgba(255, 112, 152, 0.18); stroke: #ff7098; }
.learn-chord-polygon.suspended { fill: rgba(100, 229, 223, 0.17); stroke: var(--learn-cyan); }

.learn-grid-note.is-active path {
  fill: var(--learn-gold);
  stroke: #fff1c5;
  stroke-width: 2.5;
}

.learn-grid-note.is-active text {
  fill: #171006;
  stroke: rgba(255, 255, 255, 0.18);
}

.learn-grid-note.is-active.minor path { fill: var(--learn-violet); }
.learn-grid-note.is-active.augmented path { fill: #ff9067; }
.learn-grid-note.is-active.diminished path { fill: #ff7098; }
.learn-grid-note.is-active.suspended path { fill: var(--learn-cyan); }

.learn-note.is-path-active circle,
.learn-cell-note.is-path-active path,
.learn-grid-note.is-path-active path {
  fill: #fff2bb;
  stroke: var(--learn-gold);
  stroke-width: 4;
  filter: drop-shadow(0 0 9px rgba(255, 198, 90, 0.76));
}

.learn-note.is-path-active text,
.learn-cell-note.is-path-active text,
.learn-grid-note.is-path-active text {
  fill: #181006;
  stroke: rgba(255, 255, 255, 0.2);
}

.learn-path-controls {
  margin-top: 10px;
}

.learn-stage-tab:hover,
.learn-action-button:hover,
.learn-chord-choice:hover,
.learn-icon-button:hover:not(:disabled),
.learn-reset-button:hover,
.learn-play-chord:hover {
  border-color: rgba(100, 229, 223, 0.52);
  filter: brightness(1.1);
}

.learn-stage-tab:focus-visible,
.learn-action-button:focus-visible,
.learn-chord-choice:focus-visible,
.learn-icon-button:focus-visible,
.learn-reset-button:focus-visible,
.learn-play-chord:focus-visible {
  outline: 2px solid var(--learn-cyan);
  outline-offset: 2px;
}

@media (max-width: 430px) {
  .tonnetz-learn { padding-inline: 8px; }
  .learn-card { padding: 12px 10px; border-radius: 14px; }
  .learn-current-chord { grid-template-columns: 1fr; }
  .learn-current-chord strong { grid-row: auto; }
  .learn-play-chord { grid-column: 1; }
  .learn-icon-button { min-width: 78px; }
}

@media (prefers-reduced-motion: reduce) {
  .tonnetz-learn * { scroll-behavior: auto !important; }
}