网站整体变灰-css

加入以下样式
html{
    filter: grayscale(100%);
    -webkit-filter: grayscale(100%);
    -moz-filter: grayscale(100%);
    -ms-filter: grayscale(100%);
    -o-filter: grayscale(100%);
    filter: progid:DXImageTransform.Microsoft.BasicImage(grayscale=1);
    -webkit-filter: grayscale(1);
}