body {
animation-name: anbg;
animation-duration: 30s;
animation-timing-function: ease;
animation-iteration-count: 1;
animation-fill-mode: forwards;
}
@keyframes anbg {
0% {
  background-image: url("https://wwwbin.com/images/white400.jpg");
background-size: 100vw 100vh;
}
23% {
  background-image: url("https://wwwbin.com/images/white400.jpg");
}
27% {
  background-image: url("https://localhost/wwwbin/u/0/1236/img/feed.jpg");
background-size: 100vw 100vh;
}
100% {
  background-image: url("https://localhost/wwwbin/u/0/1236/img/feed.jpg");
}
}