[ 那些技巧 ] 使整个网站变灰色

html{
    filter: grayscale(100%);
    -webkit-filter: grayscale(100%);
    -moz-filter: grayscale(100%);
    -ms-filter: grayscale(100%);
    -o-filter: grayscale(100%);
    filter: url("data:image/svg+xml;utf8,#grayscale");
    filter: progid:DXImageTransform.Microsoft.BasicImage(grayscale=1);
    filter: gray;
    -webkit-filter: grayscale(1);
}

摘自百度哀悼页面的css: