.stage-overlay {
  position: absolute;
  left: 50%;
  bottom: 16px;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  z-index: 10;
  transition: opacity .25s ease;
}
.stage-overlay.is-hidden {
  opacity: 0;
  pointer-events: none;
}

.thumbnail-rail {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.controls-panel {
  display: flex;
  align-items: center;
  gap: 8px;
  background-color: rgba(30, 32, 40, 0.75);
  backdrop-filter: blur(6px);
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: 10px;
  padding: 10px;
  box-shadow: 0 8px 24px rgba(0,0,0,0.35), 0 2px 6px rgba(0,0,0,0.25);
  transition: opacity .25s ease;
  user-select: none;
  -webkit-user-select: none;
  -webkit-touch-callout: none;
}