noise.css

.bg {
    position: fixed;
    top: -50%;
    left: -50%;
    right: -50%;
    bottom: -50%;
    width: 200%;
    height: 200vh;
    background: transparent
        url("http://assets.iceable.com/img/noise-transparent.png") repeat 0 0;
    background-repeat: repeat;
    animation: bg-animation 0.2s infinite;
    opacity: 1;
    visibility: visible;
    z-index: -2;
    will-change: transform;
}

@keyframes bg-animation {
    0% {
        transform: translate3d(0, 0, 0);
    }
    10% {
        transform: translate(-5%, -5%);
    }
    20% {
        transform: translate(-10%, 5%);
    }
    30% {
        transform: translate(5%, -10%);
    }
    40% {
        transform: translate(-5%, 15%);
    }
    50% {
        transform: translate(-10%, 5%);
    }
    60% {
        transform: translate(15%, 0);
    }
    70% {
        transform: translate(0, 10%);
    }
    80% {
        transform: translate(-15%, 0);
    }
    90% {
        transform: translate(10%, 5%);
    }
    100% {
        transform: translate(5%, 0);
    }
}