.soundtrack-control {
  position: fixed;
  bottom: 24px;
  left: 24px;
  z-index: 20;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 50%;
  color: #f4f4f4;
  background: rgba(18, 18, 18, 0.78);
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.28);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  cursor: pointer;
  transition: border-color 180ms ease, background 180ms ease, transform 180ms ease;
}

.soundtrack-control:hover {
  border-color: rgba(0, 198, 92, 0.55);
  background: rgba(24, 24, 24, 0.92);
  transform: translateY(-1px);
}

.soundtrack-control:focus-visible {
  outline: 2px solid #00c65c;
  outline-offset: 3px;
}

.soundtrack-control svg {
  flex: 0 0 auto;
  width: 18px;
  height: 18px;
  overflow: visible;
}

.soundtrack-control .sound-bar {
  fill: currentColor;
  transform-box: fill-box;
  transform-origin: center;
}

.soundtrack-control[data-state="playing"] {
  color: #00c65c;
}

.soundtrack-control[data-state="playing"] .sound-bar {
  animation: soundtrack-pulse 900ms ease-in-out infinite alternate;
}

.soundtrack-control[data-state="playing"] .sound-bar:nth-child(2) { animation-delay: -300ms; }
.soundtrack-control[data-state="playing"] .sound-bar:nth-child(3) { animation-delay: -600ms; }

.soundtrack-control[data-state="muted"] .sound-bar,
.soundtrack-control[data-state="ready"] .sound-bar {
  opacity: 0.52;
  transform: scaleY(0.45);
}

@keyframes soundtrack-pulse {
  from { transform: scaleY(0.38); }
  to { transform: scaleY(1); }
}

@media (max-width: 600px) {
  .soundtrack-control {
    bottom: 16px;
    left: 16px;
    width: 40px;
    height: 40px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .soundtrack-control,
  .soundtrack-control .sound-bar { transition: none; animation: none !important; }
}