.git-link {
    z-index: 50;
    position: fixed;
    top: 0;
    right: 0;
    border: 0;
    height: 50px;
    width: 50px;
    transform: rotate(0deg);
    -webkit-transform: rotate(0deg);
    -moz-transform: rotate(0deg);
    -o-transform: rotate(0deg);
    -ms-transform: rotate(0deg);
    background-image: url(https://images.cnblogs.com/cnblogs_com/danielZ/1510732/o_timg.jpg);
}