#scrollTopBtn {
    display: none;
    position: fixed;
    bottom: 30px;
    right: 30px;
    z-index: 9999;
    border-radius: 50%;
    width: 48px;
    height: 48px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.15);
    transition: background 0.2s, color 0.2s;
    padding: 0;
    justify-content: center;
    align-items: center;
    font-size: 22px;
}
#scrollTopBtn:hover {
    background: #ff6600;
    color: #fff;
    border-color: #ff6600;
}
#scrollTopBtn i {
    margin: 0;
    font-size: 22px;
}