#header::before {
    background-image: url(https://pic.cnblogs.com/avatar/1291484/20210514222800.png);
    background-size: contain;
    border: 0 solid #fff;
    border-radius: 150px;
    box-shadow: 0 -1px 12px -4px #000;
    content: " ";
    display: block;
    height: 150px;
    margin-bottom: 20px;
    margin-left: 50%;
    position: relative;
    transform: translate3d(-50%, 50%, 0px);
    width: 150px;
}