<!--黑客帝国背景，移动端不加入-->
<div><canvas id="matrixBG" ></canvas></div>
<script src="https://files.cnblogs.com/files/batsing/matrix.js"></script>
<script>
$(function(){
    let ua = navigator.userAgent.toLowerCase();
    if( ua.indexOf("mobile")<0 ){
      window.onload = function(){
        let matrix = new MatrixBG("matrixBG", 2);
      }
    }
});
</script>

let matrix = new MatrixBG("matrixBG", 2);

body {
    background: url("//photo.tuchong.com/1019978/f/21914120.jpg") fixed center center;
    background-repeat: no-repeat;
    background-size: cover;
}
#matrixBG{
    position: fixed; top:0; left: 0; 
    z-index: -1;
    animation: fade8 3s infinite;
}
@keyframes fade8 {
    0% {
        opacity: 0.8;
    }
    50% {
        opacity: 0.9;
    }
    100% {
        opacity: 0.8;
    }
}