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

/* Dark theme (default) */
:root {
  --bg-primary: #1a1a2e;
  --bg-secondary: #16213e;
  --bg-tertiary: #0f3460;
  --accent: #e94560;
  --accent-hover: #ff6b6b;
  --text-primary: #eee;
  --text-secondary: #aaa;
  --white-key: #fafafa;
  --white-key-active: #e94560;
  --black-key: #222;
  --black-key-active: #ff6b6b;
  --border-color: #333;
}

/* Light theme */
[data-theme="light"] {
  --bg-primary: #f5f5f7;
  --bg-secondary: #ffffff;
  --bg-tertiary: #e8e8ed;
  --accent: #d63851;
  --accent-hover: #e94560;
  --text-primary: #1d1d1f;
  --text-secondary: #6e6e73;
  --white-key: #ffffff;
  --white-key-active: #e94560;
  --black-key: #1d1d1f;
  --black-key-active: #ff6b6b;
  --border-color: #d2d2d7;
}

body {
  font-family: 'Segoe UI', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.6;
}

.container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 2rem 1rem;
}

header {
  position: relative;
  text-align: center;
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

h1 {
  font-size: 2.5rem;
  font-weight: 300;
  letter-spacing: 0.05em;
  margin-bottom: 0.25rem;
}

.subtitle {
  font-size: 1rem;
  color: var(--text-secondary);
  font-style: italic;
  margin-bottom: 0.5rem;
}

.author {
  font-size: 0.9rem;
  color: var(--accent);
}

main {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

/* Controls Section */
.controls {
  background: var(--bg-secondary);
  padding: 1.5rem;
  border-radius: 8px;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.control-group > label {
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-secondary);
}

select {
  padding: 0.75rem 1rem;
  font-size: 1rem;
  background: var(--bg-tertiary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' fill='%23aaa'%3E%3Cpath d='M6 8L1 3h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1rem center;
}

select:hover {
  border-color: var(--accent);
}

select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 2px rgba(233, 69, 96, 0.2);
}

.radio-group {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.radio-label {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.5rem 0.75rem;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  cursor: pointer;
  font-size: 0.9rem;
  transition: all 0.2s;
}

.radio-label:hover {
  border-color: var(--accent);
}

.radio-label:has(input:checked) {
  background: var(--accent);
  border-color: var(--accent);
}

.radio-label input {
  display: none;
}

/* Display Section */
.display {
  background: var(--bg-secondary);
  padding: 1.5rem;
  border-radius: 8px;
}

.info-panel {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 1rem;
  margin-bottom: 1.5rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

.info-item {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.info-label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-secondary);
}

.info-value {
  font-size: 1.25rem;
  font-weight: 600;
  font-family: 'SF Mono', 'Consolas', monospace;
}

/* Chord Quality styling */
.chord-quality-item {
  grid-column: span 2;
}

.chord-quality {
  color: var(--text-secondary);
  transition: all 0.2s;
}

.chord-quality.has-quality {
  color: var(--accent);
  font-size: 1.5rem;
}

/* Keyboard */
.keyboard-container {
  overflow-x: auto;
  padding: 1rem 0;
  margin-bottom: 1rem;
}

.keyboard {
  display: flex;
  position: relative;
  height: 140px;
  min-width: fit-content;
  margin: 0 auto;
}

.key {
  position: relative;
  cursor: pointer;
  transition: all 0.1s;
}

.key-white {
  width: 36px;
  height: 140px;
  background: var(--white-key);
  border: 1px solid #ccc;
  border-radius: 0 0 4px 4px;
  z-index: 1;
}

.key-white:hover {
  background: #f0f0f0;
}

.key-white.active {
  background: var(--white-key-active);
  border-color: var(--white-key-active);
}

.key-black {
  width: 24px;
  height: 85px;
  background: var(--black-key);
  border-radius: 0 0 3px 3px;
  margin-left: -12px;
  margin-right: -12px;
  z-index: 2;
}

.key-black:hover {
  background: #333;
}

.key-black.active {
  background: var(--black-key-active);
}

.key-label {
  position: absolute;
  bottom: 8px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 0.7rem;
  color: #666;
  pointer-events: none;
}

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

.key-black .key-label {
  color: #888;
  bottom: 6px;
  font-size: 0.6rem;
}

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

.key.bass-note {
  box-shadow: inset 0 -8px 0 var(--accent);
}

.key-white.bass-note.active {
  box-shadow: inset 0 -8px 0 #b8354a;
}

/* Play Controls */
.play-controls {
  display: flex;
  gap: 1rem;
  justify-content: center;
}

.play-btn {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 1rem 2rem;
  font-size: 1rem;
  font-weight: 600;
  background: var(--accent);
  color: white;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.2s;
}

.play-btn:hover {
  background: var(--accent-hover);
  transform: translateY(-2px);
}

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

.play-icon {
  font-size: 0.9rem;
}

/* About Section */
.about {
  background: var(--bg-secondary);
  padding: 1.5rem;
  border-radius: 8px;
}

.about h2 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 1rem;
  color: var(--accent);
}

.about p {
  margin-bottom: 0.75rem;
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.about a {
  color: var(--accent);
  text-decoration: none;
}

.about a:hover {
  text-decoration: underline;
}

.paper-link {
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border-color);
}

/* Footer */
footer {
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border-color);
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.85rem;
}

footer a {
  color: var(--accent);
  text-decoration: none;
}

footer a:hover {
  text-decoration: underline;
}

/* Theme Toggle */
.theme-toggle {
  position: absolute;
  top: 0;
  right: 0;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  padding: 0.5rem 0.75rem;
  cursor: pointer;
  color: var(--text-primary);
  font-size: 1.1rem;
  transition: all 0.2s;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.theme-toggle:hover {
  border-color: var(--accent);
  background: var(--bg-secondary);
}

.theme-toggle .theme-icon {
  font-size: 1rem;
}

/* Responsive */
@media (max-width: 600px) {
  h1 {
    font-size: 1.75rem;
  }
  
  .controls {
    grid-template-columns: 1fr;
  }
  
  .keyboard {
    transform: scale(0.85);
    transform-origin: left center;
  }
  
  .play-controls {
    flex-direction: column;
  }
  
  .play-btn {
    width: 100%;
    justify-content: center;
  }
}