<style>
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);
-webkit-filter: grayscale(1);
}
</style>