html, body {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
  background: #000;
  overflow: hidden;
}

#stage {
  position: relative;
  width: 100vw;
  height: 100vh;
}

.slide {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: contain;
  background: #000;
  opacity: 0;
  transition: opacity 1.2s ease-in-out;
}

.slide.active {
  opacity: 1;
}

#empty-message {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  color: #888;
  font-family: -apple-system, "Segoe UI", "Malgun Gothic", sans-serif;
  font-size: 1.4rem;
  text-align: center;
  line-height: 1.8;
  display: none;
}

#empty-message span {
  font-size: 1rem;
  color: #555;
}

#stage.empty #empty-message {
  display: block;
}