.git-link {
    z-index: 100;
    position: fixed;
    top: 0;
    right: 0;
    border: 0;
    height: 149px;
    width: 149px;
    background-image: url(https://img2018.cnblogs.com/blog/389840/201909/389840-20190911095437536-1728856464.png);
}