Template:Youtube/styles.css

.slider {
  left: 0%;
  animation: slide 4s linear forwards;
}

@keyframes slide {
  0% {
    left: 0%;
    opacity: 1;
  }
  
  100% {
    left: 100%;
  }
}

.sliderbg {
  background:linear-gradient(red 100%,grey 100%);
  animation: slidebg 4s linear forwards;
}

@keyframes slidebg {
  0% {
    background:linear-gradient(red 0%,grey 0%);
    opacity: 1;
  }
  
  100% {
    background:linear-gradient(red 100%,grey 100%);
  }
}