body:before {
    background: url(https://images.cnblogs.com/cnblogs_com/haijian/1663538/o_200307074053BZ_1.jpg) center/cover no-repeat;
    content: '';
   background-repeat: no-repeat;
    background-position: center;
    opacity: 0.1;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    -webkit-filter: grayscale(40%);
    -moz-filter: grayscale(40%);
    -ms-filter: grayscale(40%);
    -o-filter: grayscale(40%);
    filter: grayscale(40%);
    filter: gray;
}

/* 隐藏反对按钮 */
#.buryit {
display:none;
}

/*隐藏广告*/
ad_t2, #cnblogs_c1, #under_post_news, #cnblogs_c2, #under_post_kb {
    display: none;
}