.topBtn {
    position: fixed;
    background: #73B4AA;
    color: #fff;
    text-decoration: none;
    font-size: 18px;
    font-family: "uddigikyokasho-pro";
    width: 200px;
    height: 60px;
    text-align: center;
    line-height: 60px;
    box-sizing: border-box;
    z-index: 99999;
    border-radius: 30px;
    left: 50%;
    transform: translateX(-50%);
}

.topBtn:hover {
    background: #777;
}