.corner{
    width: 40px;
    position: fixed;
    bottom: 25px;
    right: 0;
    cursor: pointer;
}
.corner .to-serve{
    width: 40px;
    height: 40px;
    background: rgba(230, 37, 38, 0.7);
    text-align: center;
    line-height: 40px;
    margin-bottom: 3px;
}
.corner i{
    color: #EDDFE0;
    font-size: 30px;
}
.corner .to-top{
    width: 40px;
    height: 40px;
    background: #A4A4A4;
    text-align: center;
    line-height: 40px;
    display: none;
}