.subtitle {
  position: fixed;
  left: 0;
  right: 0;
  padding: 10px;
  background-color: rgba(0, 0, 0, 0.5);
  color: #fff;
  font-size: 16px;
  text-align: center;
  animation: subtitle-animation 5s linear forwards;
}

@keyframes subtitle-animation {
  0% {
    bottom: -100px;
  }
  100% {
    bottom: 0;
  }
}