html, body{
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    color: #eee;
}

body{
    background-image: url('/static/images/index_bg.jpg');
    background-size: cover; /* 将图片调整到完全覆盖容器 */
    background-repeat: no-repeat; /* 禁止重复 */
    background-position: center center; /* 居中对齐 */
    background-attachment: fixed;
}