:root {
  font-family: "Segoe UI", Roboto, sans-serif;
  color: #14213d;
  background-color: #f8f9fa;
  line-height: 1.6;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.app-header,
.app-footer {
  background: #14213d;
  color: #f8f9fa;
  padding: 1.5rem;
  text-align: center;
}

.app-header h1 {
  margin: 0 0 0.5rem 0;
  font-size: 2rem;
}

.tagline {
  margin: 0;
  font-size: 1rem;
}

.app-footer {
  font-size: 0.9rem;
}

main {
  flex: 1;
  padding: 2rem 1rem 3rem;
  display: flex;
  justify-content: center;
}

.midi-app {
  width: min(900px, 100%);
  display: grid;
  gap: 1.5rem;
}

fieldset {
  border: 1px solid #d1d9e6;
  border-radius: 0.5rem;
  padding: 1.5rem;
  background-color: #ffffff;
}

legend {
  font-weight: 600;
  padding: 0 0.5rem;
}

.upload-label,
.tempo-label {
  font-weight: 600;
  display: block;
  margin-bottom: 0.5rem;
}

input[type="file"] {
  display: block;
  margin-bottom: 0.75rem;
}

.helper-text {
  font-size: 0.9rem;
  color: #495057;
  margin: 0;
}

.file-details {
  background: #ffffff;
  border-radius: 0.5rem;
  padding: 1rem 1.5rem;
  border: 1px solid #d1d9e6;
}

.track-list {
  display: grid;
  gap: 1rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.track-list-item {
  border: 1px solid #d1d9e6;
  border-radius: 0.5rem;
  padding: 1rem 1.25rem;
  background: #fdfdfd;
  display: grid;
  gap: 0.75rem;
}

.track-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}

.track-name {
  font-weight: 600;
  font-size: 1rem;
}

.mute-toggle {
  font-size: 0.9rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.track-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.5rem;
  margin: 0;
}

.track-stats dt {
  font-size: 0.75rem;
  text-transform: uppercase;
  color: #6c757d;
  letter-spacing: 0.08em;
}

.track-stats dd {
  margin: 0;
  font-weight: 500;
}

.empty-state {
  margin: 0;
  color: #6c757d;
}

.controls {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
}

button {
  border: none;
  background: #fca311;
  color: #14213d;
  padding: 0.6rem 1.2rem;
  border-radius: 999px;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

button:disabled {
  background: #ced4da;
  color: #6c757d;
  cursor: not-allowed;
  box-shadow: none;
}

button:not(:disabled):hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(20, 33, 61, 0.18);
}

#tempo-slider {
  accent-color: #fca311;
  min-width: 160px;
}

.tempo-value {
  font-weight: 600;
}

@media (max-width: 600px) {
  main {
    padding: 1.5rem 0.75rem 2.5rem;
  }

  fieldset {
    padding: 1.25rem;
  }

  .track-stats {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}