/* 返回顶部按钮样式 */
.back-to-top {
    position: fixed;
    bottom: 25px;
    right: 25px;
    display: none;
    width: 40px;
    height: 40px;
    line-height: 40px;
    text-align: center;
    background-color: #337ab7;
    color: white;
    border-radius: 50%;
    box-shadow: 0 2px 5px rgba(0,0,0,0.3);
    z-index: 99;
    text-decoration: none;
    transition: background-color 0.3s;
}

.back-to-top:hover {
    background-color: #286090;
    color: white;
    text-decoration: none;
}

.back-to-top i {
    font-size: 18px;
}