.scanlines {
    position: relative;
    overflow: hidden;
}

.scanlines:before,
.scanlines:after {
    display: block;
    pointer-events: none;
    content: '';
    position: absolute;
}

/* Unique scanline travelling on the screen */
.scanlines:before {
    width: 100%;
    height: 2px;
    z-index: 2147483649;
    background: rgba(0, 0, 0, 0.3);
    opacity: 0.75;
    animation: scanline 6s linear infinite;
}

/* The scanlines */
.scanlines:after {
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    z-index: 2147483648;
    background: linear-gradient(
        to bottom,
        transparent 50%,
        rgba(0, 0, 0, 0.3) 51%
    );
    background-size: 100% 4px;
    animation: scanlines 1s steps(60) infinite;
}

/* ANIMATE UNIQUE SCANLINE */
@keyframes scanline {
    0% {
        transform: translate3d(0, 200000%, 0);
    }
}

@keyframes scanlines {
    0% {
        background-position: 0 50%;
    }
}