/* 加载过渡样式 - 通用CSS */
#loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: #f9fafb;
    z-index: 9999;
    transition: opacity 0.3s ease-out;
}

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

/* 主内容初始隐藏 */
main {
    opacity: 0;
    transition: opacity 0.3s ease-in;
}

main.visible {
    opacity: 1;
}