body{ 
    font-family: Microsoft YaHei,'宋体' , Tahoma, Helvetica, Arial, "\5b8b\4f53", sans-serif;
    background-color: #F1F1F1;
}
.vertical-center{
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}
img{
    max-width:100%;
}