html, body {
    background-color: #f8f8f8;
    /* 关键代码：应用黑白滤镜到整个页面 */
    filter: grayscale(100%);
    -webkit-filter: grayscale(100%);
    -moz-filter: grayscale(100%);
    -ms-filter: grayscale(100%);
    -o-filter: grayscale(100%);
}
  

/* 确保SVG图标也变黑白 */
svg {
    filter: grayscale(100%);
}