:root {
  color-scheme: dark;
  font-family: "Inter", "Noto Sans", "PingFang SC", system-ui, sans-serif;
  background: #0c0e14;
  color: #e7eaf0;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background: radial-gradient(circle at top, #151b2b 0%, #0c0e14 45%, #090b11 100%);
}

.app {
  max-width: 1200px;
  margin: 0 auto;
  padding: 48px 32px 64px;
  display: grid;
  gap: 32px;
}

.app__header {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  justify-content: space-between;
  align-items: flex-start;
}

.app__eyebrow {
  letter-spacing: 0.24em;
  text-transform: uppercase;
  font-size: 12px;
  color: #8c95aa;
  margin: 0 0 12px;
}

h1 {
  font-size: 32px;
  margin: 0 0 8px;
}

.app__subtitle {
  margin: 0;
  color: #aab2c4;
}

.app__controls {
  display: flex;
  flex-direction: column;
  gap: 16px;
  min-width: min(540px, 100%);
  background: rgba(16, 21, 34, 0.7);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 16px;
  padding: 18px;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.35);
}

.controls-row {
  display: grid;
  gap: 16px;
}

.controls-row--primary {
  grid-template-columns: repeat(2, 1fr);
}

.controls-row--secondary {
  grid-template-columns: repeat(3, 1fr);
}

.controls-row--secondary#arpeggioControls {
  grid-template-columns: repeat(2, 1fr);
}

.control {
  display: grid;
  gap: 8px;
  font-size: 13px;
  color: #94a0b7;
}

select {
  background: #0b0f1a;
  color: #e7eaf0;
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 10px;
  padding: 8px 12px;
  font-size: 14px;
}

.fretboard {
  background: rgba(12, 16, 26, 0.9);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: 20px;
  padding: 24px;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.03);
}

.fretboard__legend {
  display: grid;
  grid-template-columns: 48px repeat(25, minmax(32px, 1fr));
  gap: 8px;
  margin-bottom: 16px;
  font-size: 12px;
  color: #7d879d;
}

.fretboard__legend span {
  text-align: center;
  position: relative;
}

/* Fret marker dots */
.fret-legend--marker::before {
  content: '';
  position: absolute;
  top: -8px;
  left: 50%;
  transform: translateX(-50%);
  width: 5px;
  height: 5px;
  background: rgba(255, 255, 255, 0.5);
  border-radius: 50%;
}

.fretboard__grid {
  display: grid;
  gap: 10px;
}

.string-row {
  display: grid;
  grid-template-columns: 48px repeat(25, minmax(32px, 1fr));
  gap: 8px;
  align-items: center;
  position: relative;
}

/* Horizontal string line */
.string-row::after {
  content: '';
  position: absolute;
  left: 48px;
  right: 0;
  top: 50%;
  height: 1px;
  background: rgba(255, 255, 255, 0.12);
  transform: translateY(-50%);
  z-index: 0;
  pointer-events: none;
}

.string-label {
  text-align: center;
  font-size: 12px;
  color: #9aa6bd;
}

.note-cell {
  display: grid;
  place-items: center;
  height: 32px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.04);
  color: #78839a;
  font-size: 12px;
  border: 1px solid rgba(255, 255, 255, 0.06);
  position: relative;
  z-index: 1;
}

.note-cell--in-scale {
  color: #e7eaf0;
  background: linear-gradient(120deg, rgba(86, 130, 255, 0.18), rgba(82, 212, 255, 0.22));
  border-color: rgba(120, 165, 255, 0.6);
  box-shadow: 0 6px 18px rgba(38, 73, 156, 0.35);
}

.note-cell--root {
  background: linear-gradient(120deg, rgba(246, 178, 87, 0.22), rgba(255, 120, 90, 0.3));
  border-color: rgba(246, 178, 87, 0.8);
  color: #fff3e4;
  box-shadow: 0 6px 20px rgba(255, 120, 90, 0.4);
}

.note-cell--muted {
  color: #626d83;
}

.note-cell--open {
  border-style: dashed;
}

.note-cell--playing {
  transform: scale(1.15);
  box-shadow: 0 0 20px rgba(120, 165, 255, 0.6);
  transition: transform 0.1s ease-out;
}

.ear-training {
  background: rgba(16, 21, 34, 0.7);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 16px;
  padding: 24px;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.35);
}

.ear-training__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
  gap: 16px;
  flex-wrap: wrap;
}

.ear-training__header h2 {
  font-size: 20px;
  margin: 0;
  display: flex;
  align-items: center;
  gap: 12px;
}

.ear-training__subtitle {
  font-size: 14px;
  color: #8c95aa;
  font-weight: normal;
}

.ear-training__toggle {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 0;
  cursor: pointer;
}

.ear-training__toggle input[type="checkbox"] {
  width: 18px;
  height: 18px;
  cursor: pointer;
}

.ear-training__controls {
  display: grid;
  gap: 16px;
}

.ear-training__exercise {
  display: flex;
  gap: 16px;
  align-items: flex-end;
  flex-wrap: wrap;
}

.ear-training__exercise .control {
  flex: 1;
  min-width: 200px;
}

.btn {
  padding: 10px 24px;
  border-radius: 10px;
  border: none;
  font-size: 14px;
  cursor: pointer;
  transition: all 0.2s;
}

.btn--primary {
  background: linear-gradient(120deg, #5682ff, #52d4ff);
  color: white;
  font-weight: 500;
}

.btn--primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 8px 20px rgba(86, 130, 255, 0.4);
}

.btn--primary:active {
  transform: translateY(0);
}

.ear-training__feedback {
  min-height: 40px;
  padding: 12px 16px;
  border-radius: 10px;
  font-size: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.06);
}

.ear-training__feedback.correct {
  background: linear-gradient(120deg, rgba(34, 197, 94, 0.15), rgba(74, 222, 128, 0.2));
  border-color: rgba(74, 222, 128, 0.5);
  color: #86efac;
}

.ear-training__feedback.incorrect {
  background: linear-gradient(120deg, rgba(239, 68, 68, 0.15), rgba(248, 113, 113, 0.2));
  border-color: rgba(248, 113, 113, 0.5);
  color: #fca5a5;
}

.ear-training__stats {
  text-align: center;
  color: #94a0b7;
  font-size: 14px;
}

.note-cell.clickable {
  cursor: pointer;
  transition: all 0.15s;
}

.note-cell.clickable:hover {
  transform: scale(1.1);
  box-shadow: 0 0 20px rgba(120, 165, 255, 0.5);
}

.note-cell.selected {
  background: linear-gradient(120deg, rgba(168, 85, 247, 0.25), rgba(192, 132, 252, 0.3));
  border-color: rgba(192, 132, 252, 0.8);
  box-shadow: 0 0 25px rgba(168, 85, 247, 0.6);
  animation: pulse 0.3s ease-out;
}

@keyframes pulse {
  0% { transform: scale(1); }
  50% { transform: scale(1.15); }
  100% { transform: scale(1); }
}

/* TODO Section */
.todo-section {
  background: rgba(16, 21, 34, 0.5);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: 12px;
  padding: 20px 24px;
  margin-top: 32px;
}

.todo-section h3 {
  margin: 0 0 12px 0;
  font-size: 16px;
  color: #94a0b7;
  font-weight: 500;
}

.todo-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.todo-list li {
  padding-left: 24px;
  position: relative;
  color: #7d879d;
  font-size: 14px;
}

.todo-list li::before {
  content: '□';
  position: absolute;
  left: 0;
  color: rgba(255, 255, 255, 0.3);
}

/* Footer */
.app-footer {
  margin-top: 48px;
  padding-top: 32px;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
  text-align: center;
}

.quote {
  font-size: 16px;
  font-style: italic;
  color: #aab2c4;
  margin: 0 0 8px 0;
  line-height: 1.6;
}

.quote-author {
  font-size: 14px;
  color: #7d879d;
  margin: 0;
}

.developer-credit {
  margin-top: 24px;
  font-size: 13px;
  color: #626d83;
}

.developer-credit a {
  color: #5682ff;
  text-decoration: none;
  transition: color 0.2s;
}

.developer-credit a:hover {
  color: #52d4ff;
  text-decoration: underline;
}

@media (max-width: 900px) {
  .fretboard__legend,
  .string-row {
    grid-template-columns: 48px repeat(13, minmax(32px, 1fr));
  }

  .ear-training__exercise {
    flex-direction: column;
    align-items: stretch;
  }

  .quote {
    font-size: 14px;
  }
}