@keyframes {
  0%: left;
  100%: right;
}
.banner {
  background-image: url("https://files.catbox.moe/z8904w.png");
  background-color: black;
  animation-name: banner;
  animation-duration: 4s;
  animation-delay: 2s;
  animation-iteration-count: infinite;
  animation-direction: normal;
  background-repeat: repeat-x;
}