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

:root {
  --bg-primary: #0B0F1A;
  --bg-secondary: #12182A;
  --bg-elevated: #1A2238;

  --accent-primary: #4DA3FF;
  --accent-secondary: #7C5CFF;
  --accent-glow: rgba(77,163,255,0.25);

  --text-primary: #E6EAF2;
  --text-secondary: #9AA4BF;
  --text-muted: #5C6785;

  --bg-card: #1e2746;

  --border-primary: #aad2e5;
  --border-subtle: rgba(255,255,255,0.06);

  --white-key: #f8f9fb;
  --white-key-hover: #e3e7ef;

  --black-key: #222;
  --black-key-hover: #333;

  --chord-color: var(--accent-secondary);
  --chord-glow: var(--accent-primary);
  --scale-color: #4a90d9;
  --border-color: #2a2a4a;
  --radius: 8px;
  --transition: all 0.3s ease;
}

body {
  font-family: 'Inter', sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}

/* Header */
.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 24px;
  background: var(--bg-elevated);
  border-bottom: 1px solid var(--border-color);
  gap: 20px;
}

.header-left {
  display: flex;
  flex-direction: column;
}

.app-logo {
  font-size: 28px;
  font-weight: 700;
  letter-spacing: 2px;
  color: var(--text-primary);
}

.logo-accent {
  color: var(--accent);
}

.app-subtitle {
  font-size: 12px;
  color: var(--text-muted);
  letter-spacing: 1px;
  text-transform: uppercase;
}

/* Control Panel */
.control-panel {
  margin: 20px;
  padding: 20px 24px;
  border-radius: 14px;
  border: 1px solid var(--border-subtle);
  background: var(--bg-secondary);
}

.control-row {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.control-group {
  width: 100%;
  border: 1px solid var(--border-color);
  border-radius: 10px;
}

.control-group .root-select {
  display: flex;
  width: 100%;
  background: var(--bg-primary);
  border-radius: 10px;
}

.control-group .scale-select {
  display: flex;
  flex-wrap: wrap;
  width: 100%;
  border-radius: 10px;
  background: var(--bg-primary);
}

.control-group .selector {
  cursor: pointer;
  padding: 10px 0;
  color: var(--text-secondary);
  display: flex;
  border: 1px solid transparent;
  border-radius: 10px;
  text-align: center;
  justify-content: center;
  align-items: center;
  flex: 1 1 auto;
}

.control-group .selector-name {
  border-right: 1px solid var(--border-subtle);
  padding: 0 10px;
  width: 100%;
}

.control-group .selector:last-child .selector-name {
  border: none
}

.control-group .selector:hover {
  color: var(--text-primary);
  border: 1px solid transparent;
  box-shadow: inset 0 0 10px var(--accent-secondary);
  background: linear-gradient(var(--bg-card), var(--bg-card)) padding-box, linear-gradient(45deg, var(--accent-primary), var(--accent-secondary)) border-box;
}

.control-group .selector.selected {
  background: linear-gradient(45deg, var(--accent-primary), var(--accent-secondary));
  color: var(--text-primary);
  border: 1px solid transparent;
  box-shadow: inset 0 0 10px var(--accent-secondary);
  background: linear-gradient(var(--bg-card), var(--bg-card)) padding-box, linear-gradient(45deg, var(--accent-primary), var(--accent-secondary)) border-box;

}

/* Visualization */
.visualization-container {
  padding: 24px;
  flex: 1;
}

.panel {
  background: var(--bg-secondary);
  border-radius: 16px;
  padding: 20px;
  border: 1px solid var(--border-color);
  overflow: hidden;
}

.visual-container {
  position: relative;
}

.key-container {
  position: absolute;
  display: flex;
  justify-content: center;
  align-items: center;
}

/* Piano */
.piano-panel {
  display: flex;
  justify-content: center;
  align-items: center;
  width: 100%;
  height: 300px;
}

.piano-keyboard {
  position: relative;
  height: 250px;
}

.white-keys {
  display: flex;
  height: 100%;
}

.black-keys {
  position: absolute;
  top: 0;
  left: 0;
  height: 60%;
  width: 100%;
}

.piano-key {
  cursor: pointer;
  box-sizing: border-box;
  border-width: 1px;
  border-style: solid;
  border-color: black;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-end;
  border-radius: 5px;
  position: relative;
}

.white-key {
  position: relative;
  background-color: var(--white-key);
  border-bottom: 10px solid #c8cace;
  border-bottom-left-radius: 10px;
  border-bottom-right-radius: 10px;
  z-index: 1;
}

.white-key:hover {
  border-bottom-width: 7px;
  background-image: linear-gradient(to bottom, var(--white-key), var(--white-key-hover));
}

.black-key {
  position: absolute;
  background-image: linear-gradient(to bottom, black, var(--black-key));
  border-bottom: 10px solid black;
  border-bottom-left-radius: 10px;
  border-bottom-right-radius: 10px;
  z-index: 2;
  transform: translateX(-50%);
}

.black-key:hover {
  background-image: linear-gradient(to bottom, black, var(--black-key-hover));
  border-bottom-width: 7px;
}

.chord-dot {
  width: 25px;
  height: 25px;
  margin: 10px;
  border-radius: 50%;
  pointer-events: none;
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 2;
  background-color: var(--accent-secondary)
}

.key-label {
  font-size: 15px;
  font-weight: 500;
  pointer-events: none;
  z-index: 4;
  margin-bottom: 10px;
}

.white-key .key-label {
  color: black;
}

.black-key .key-label {
  color: white;
}


.white-key.scale-gradient {
  background-image: linear-gradient(to top, var(--accent-primary), var(--white-key));
  box-shadow: inset 0 0 20px 10px var(--white-key);
}

.black-key.scale-gradient {
  color: var(--text-primary);
  background-image: linear-gradient(to top, var(--accent-secondary), var(--black-key));
  box-shadow: inset 0 0 10px 10px var(--black-key);
}

/* Chord Explorer */
.chord-explorer {
  padding: 24px;
}

.chord-explorer-header {
  padding: 16px 0;
  font-size: 20px;
  font-weight: 600;
  color: var(--text-primary);
}

.chord-explorer .chord-audio {
  display: flex;
  width: 100%;
  justify-content: center;
  gap: 15px;
  margin-bottom: 20px;
}

.chord-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  background-color: var(--bg-secondary);
}

.chord-explorer .button {
  color: var(--text-muted);
  cursor: pointer;
  background: var(--bg-elevated);
  padding: 20px;
  border-radius: 10px;
  border: 1px solid var(--border-color);
  align-content: center;
  justify-content: center;
  font-weight: 700;
}

.chord-explorer .button:hover {
  color: var(--text-primary);
  border: 1px solid transparent;
  box-shadow: inset 0 0 10px var(--accent-secondary);
  background: linear-gradient(var(--bg-card), var(--bg-card)) padding-box, linear-gradient(45deg, var(--accent-primary), var(--accent-secondary)) border-box;
}

.chord-grid {
  display: flex;
  gap: 12px;
  padding: 16px 0;
  flex-wrap: wrap;
  justify-content: center;
}

.chord-card {
  width: 150px;
  color: var(--text-muted);
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 14px 12px;
  cursor: pointer;
  text-align: center;
}

.chord-card:hover {
  color: var(--text-primary);
  border: 1px solid transparent;
  box-shadow: inset 0 0 10px var(--accent-secondary);
  background: linear-gradient(var(--bg-card), var(--bg-card)) padding-box, linear-gradient(45deg, var(--accent-primary), var(--accent-secondary)) border-box;
}

.chord-card.active {
  color: var(--text-primary);
  border: 1px solid transparent;
  box-shadow: inset 0 0 10px var(--accent-secondary);
  background: linear-gradient(var(--bg-card), var(--bg-card)) padding-box, linear-gradient(45deg, var(--accent-primary), var(--accent-secondary)) border-box;
}

.chord-degree {
  font-size: 12px;
  font-weight: 700;
  margin-bottom: 6px;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.chord-name {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 8px;
}

.chord-notes {
  display: flex;
  justify-content: center;
  gap: 4px;
  margin-bottom: 6px;
}

.chord-note {
  display: inline-block;
  padding: 2px 6px;
  background: rgba(74, 144, 217, 0.12);
  border-radius: 4px;
  font-size: 12px;
  font-weight: 600;
  color: var(--accent-light);
}

.chord-important {
  border: 2px solid var(--accent-secondary);
  width: 20px;
  height: 20px;
  border-radius: 50%;

  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 10px;
  font-weight: bold;

  position: absolute;
}

.chord-formula {
  font-size: 11px;
  color: var(--text-muted);
  font-family: monospace;
}

/* Footer */
.app-footer {
  padding: 12px 24px;
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  margin-top: auto;
}

/* Responsive */
@media (max-width: 900px) {
  .app-header {
    flex-wrap: wrap;
    padding: 12px 16px;
  }

  .control-panel {
    padding: 16px;
  }

  .control-row {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }

  .control-group select {
    width: 100%;
  }

  .chord-grid {
    grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
  }
}

@media (max-width: 600px) {
  .app-logo {
    font-size: 22px;
  }

  .app-subtitle {
    display: none;
  }

  .scale-name {
    font-size: 18px;
  }

  .scale-notes {
    font-size: 15px;
  }

  .chord-grid {
    grid-template-columns: repeat(3, 30%);
  }
  .control-group .selector {
    padding: 5px;
  }
}