html.hover{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);
}