404.html

<canvas id="canvas" hidden></canvas>
<div class="center">
     <h1>404</h1>

    <p>PAGE NOT FOUND.</p>
</div>

<style>
 @import url(https://fonts.googleapis.com/css?family=Oswald:400, 700);
 html, body {
    height: 100%;
    width: 100%;
    margin: 0;
    padding: 0;
    background: #242424;
    font-family:'Oswald', sans-serif;
    background: -webkit-canvas(noise);
    background: -moz-element(#canvas);
    overflow: hidden;
}
html::after {
    content:'';
    background: radial-gradient(circle, rgba(0, 0, 0, 0), rgba(0, 0, 0, 1));
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
}
.center {
    height: 400px;
    width: 500px;
    position: absolute;
    top: calc(50% - 200px);
    left: calc(50% - 250px);
    text-align: center;
}
h1, p {
    margin: 0;
    padding: 0;
    -webkit-animation: funnytext 4s ease-in-out infinite;
    animation: funnytext 4s ease-in-out infinite;
}
h1 {
    font-size: 16rem;
    color: rgba(0, 0, 0, 0.3);
    -webkit-filter: blur(3px);
    filter: blur(3px);
}
p {
    font-size: 2rem;
    color: rgba(0, 0, 0, 0.6);
}
body::after, body::before {
    content:' ';
    display:block;
    position:absolute;
    left:0;
    right:0;
    top:-4px;
    height:4px;
    -webkit-animation: scanline 8s linear infinite;
    animation: scanline 8s linear infinite;
    opacity: 0.33;
    background: linear-gradient(to bottom, rgba(0, 0, 0, 0), rgba(0, 0, 0, 0.5) 90%, rgba(0, 0, 0, 0)), -webkit-canvas(noise);
    background: linear-gradient(to bottom, rgba(0, 0, 0, 0), rgba(0, 0, 0, 0.5) 90%, rgba(0, 0, 0, 0)), -moz-element(#canvas);
}
body::before {
    -webkit-animation-delay: 4s;
    animation-delay: 4s;
}
@-webkit-keyframes scanline {
    0% {
        top:-5px;
    }
    100% {
        top:100%;
    }
}
@keyframes scanline {
    0% {
        top:-5px;
    }
    100% {
        top:100%;
    }
}
@-webkit-keyframes funnytext {
    0% {
        color: rgba(0, 0, 0, 0.3);
        -webkit-filter: blur(3px);
    }
    30% {
        color: rgba(0, 0, 0, 0.5);
        -webkit-filter: blur(1px);
    }
    65% {
        color: rgba(0, 0, 0, 0.2);
        -webkit-filter: blur(5px);
    }
    100% {
        color: rgba(0, 0, 0, 0.3);
        -webkit-filter: blur(3px);
    }
}
@keyframes funnytext {
    0% {
        color: rgba(0, 0, 0, 0.3);
        filter: blur(3px);
    }
    30% {
        color: rgba(0, 0, 0, 0.5);
        filter: blur(1px);
    }
    65% {
        color: rgba(0, 0, 0, 0.2);
        filter: blur(5px);
    }
    100% {
        color: rgba(0, 0, 0, 0.3);
        filter: blur(3px);
    }
}
</style>

<script>
  var canvas = document.getElementById('canvas'),
    context = canvas.getContext('2d'),
    height = canvas.height = 256,
    width = canvas.width = height,
    bcontext = 'getCSSCanvasContext' in document ? document.getCSSCanvasContext('2d', 'noise', width, height) : context;
noise();

function noise() {
    requestAnimationFrame(noise);
    var idata = context.getImageData(0, 0, width, height);
    for (var i = 0; i < idata.data.length; i += 4) {
        idata.data[i] = idata.data[i + 1] = idata.data[i + 2] = Math.floor(Math.random() * 255);
        idata.data[i + 3] = 255;
    }
    bcontext.putImageData(idata, 0, 0);
}
</script>