@keyframes pubc-block1{
    0%{
        transform: translateY(0);
    }
    50%{
        transform: translateY(-20px);
    }
    100%{
        transform: translateY(20px);
    }
}
@media screen and (min-width:750px){
    .pubc-block1 .item{
        animation: pubc-block1 2.6s linear 0s infinite alternate;
    }
    .pubc-block1 .item:hover{
        
  animation-play-state:paused;
  -webkit-animation-play-state:paused; /* Safari 和 Chrome */
    }
    .pubc-block1 .item.i1{
        animation-delay: 0s;
    }
    .pubc-block1 .item.i2{
        animation-delay: 0.2s;
    }
    .pubc-block1 .item.i3{
        animation-delay: 0.4s;
    }
    .pubc-block1 .item.i4{
        animation-delay: 0.6s;
    }
}