灰色网站

html {
filter: gray !important;
filter:progidDXImageTransform.Microsoft.BasicImage(grayscale=1);
filter:grayscale(100%);
-webkit-filter:grayscale(100%);
-moz-filter:grayscale(100%);
-ms-filter:grayscale(100%);
-o-filter:grayscale(100%); 
}

https://blog.csdn.net/qq_40138556/article/details/105298546