/* 加载动画样式 */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: #fff;
    z-index: 9999;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: opacity 0.3s ease;
}

.loading-overlay.hidden {
    opacity: 0;
    pointer-events: none;
}

.loading-spinner {
    width: 50px;
    height: 50px;
    border: 3px solid #f3f3f3;
    border-top: 3px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* 返回顶部按钮样式 */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 40px;
    height: 40px;
    color: white;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    opacity: 0;
    transition: opacity 0.3s ease;
    z-index: 99;
    font-size: 12px;
    color: #fff;
    line-height: 1;
    padding: 6px;
}

.back-to-top.visible {
    opacity: 1;
}