.qr-code {
        display: none;
        position: absolute;
        top: 0;
        right: 50px;
        width: 100px;
        height: 100px;
        background-color: white;
        border: 1px solid #ccc;
        padding: 0px;
        box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);}
    a:hover + .qr-code {
        display: block;}
.ny_def li{min-height: 100px;}
.ny_c {display: flex;align-items: center;}
.serch{background:url(https://youth.aust.edu.cn/skin/images/ss.png) no-repeat 50% 50%;}