.my_kefu {
    position: fixed;
    width: auto;
    top: 40%;
    right: 0px;
    z-index: 99;
}

.my_kefu ul li {
    background: #424242;
    width: 20px;
    height: 50px;
    margin-bottom: 10px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    border-radius: 10px;
    padding: 0px 15px;
}

.my_kefu_item img {
    width: 30px;
}

.my_kefu_item {
    display: flex;
    align-items: center;
    justify-content: space-around;
    color: white;
}

.my_kefu ul li:hover {
    cursor: pointer;
    background: red;
}

.my_kefu_img {
    display: none;
    width: 140px;
    height: auto;
    position: absolute;
    right: 4rem;
    background: #ffffff;
    color: white;
}

.my_kefu_img img {
    width: 100%;
}

.my_kefu_hidden {
    display: none;
    flex-direction: row;
    justify-content: center;
    align-items: center;
    z-index: 999;
    height: 50px;
    border-radius: 10px;
    width: auto;
    background: red;
    color: #fff;
    padding: 0px 20px;
}

.my_kefu_hidden img {
    width: 30px;
}

.my_kefu_hidden a {
    display: flex;
    flex-direction: row;
    width: 140px;
    align-items: center;
    color: #fff;
    justify-content: center;
}

.my_kefu_hidden>div {
    display: flex;
    flex-direction: column;
    min-width: 120px;
}

.my_kefu ul li:hover .my_kefu_item {
    display: none;
}

.my_kefu ul li:hover .my_kefu_hidden {
    display: flex;
    flex-direction: row;
    text-align: center;
    position: absolute;
    right: 0px;
}

.my_kefu ul li:hover .my_kefu_img {
    display: flex;
}

#back_top {
    color: #fff;
}