.block {
    position: fixed;
    top: 50%;
    left: 50%;
    width: 100px;
    height: 100px;
    margin: -50px 0 0 -50px;
    background-color: #1989fa;
}

.van-enter-active-class,
.van-leave-active-class {
    transition-property: background-color, transform;
}

.van-enter-class,
.van-leave-to-class {
    background-color: red;
    transform: rotate(-360deg) translate3d(-100%, -100%, 0);
}