#scrollToTopBtn {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background-color: #333;
    color: #fff;
    border: none;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    font-size: 24px;
    text-align: center;
    line-height: 50px;
    cursor: pointer;
    opacity: 0;
    transition: opacity 0.3s ease;
}

#scrollToTopBtn.show {
    opacity: 1;
}