body {
    margin: 0;
    padding: 0;
}

.top-button {
    position: fixed;
    bottom: 20px;
    right: 20px;
    width: 40px;
    height: 40px;
    background-color: #FF9800;
    color: white;
    text-align: center;
    font-size: 24px;
    line-height: 40px;
    border-radius: 50%;
    cursor: pointer;
    display: inline-block;
    z-index: 9999;
}

.top-button.show {
    display: block;
    z-index: 9999;
}