/* back-to-top.css */
#back-to-top {
    position: fixed;
    bottom: 1rem;
    right: 1rem;
    width: 50px;
    height: 50px;
    background: black;
    color: white;
    text-align: center;
    line-height: 50px;
    border-radius: 50%;
    display: none;
    font-size: 20px;
    z-index: 999;
    transition: all 0.3s ease;
    text-decoration: none;
    cursor: pointer;
}
#back-to-top:hover {
    background: black;
    transform: translateY(-3px);
}

/* 响应式设计 */
@media (max-width: 768px) {
    #back-to-top {
        bottom: 20px;
        right: 20px;
        width: 40px;
        height: 40px;
        line-height: 40px;
        font-size: 16px;
    }
}