实现水平居中垂直居中的案例

.son{
    position:absolute;
    left:50%;
    transform:translate(-50%,0);
}

.son{
    position:absolute;
    top:50%;
    -webkit-transform: translate(-50%,-50%);  
    -ms-transform: translate(-50%,-50%);
    transform: translate(-50%,-50%);
}

.login-box{
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%,-50%);
}