/* 博客园背景图 https://images.cnblogs.com/cnblogs_com/blogs/83355…0154346_%E5%88%9D%E9%9F%B3%E6%9C%AA%E6%9D%A5.jpeg https://images.cnblogs.com/cnblogs_com/blogs/833558/galleries/2427286/o_241020154326_13170.webp*/
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    content: '';
    background-repeat: no-repeat;
    background-position: center;
    opacity: 0.25;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
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    -moz-filter: grayscale(40%);
    -ms-filter: grayscale(40%);
    -o-filter: grayscale(40%);
    filter: grayscale(40%);
    filter: rgb(123, 139, 164);
}