TV effect

<style>
.lines {
position: fixed;
left: 0;
top: 0;
width: 100vw;
height: 100vh;
pointer-events: none;
z-index: 300;
opacity: 0.05;
}

.lines:before {
content: '';
position: absolute;
left: 0;
top: 0;
right: 0;
bottom: 0;
pointer-events: none;
background: linear-gradient(to bottom, transparent 50%, rgba(0, 0, 0, .5) 51%);
background-size: 100% 4px;
will-change: background, background-size; animation: scanlines 0.2s linear infinite;
}

@keyframes scanlines {
from {
background: linear-gradient(to bottom, transparent 10%, rgba(0, 0, 0, .5) 51%); background-size: 100% 4px; }
to {
background: linear-gradient(to bottom, rgba(0, 0, 0, .5) 50%, transparent 51%);
background-size: 100% 4px;
}
}
@media only screen and (max-width: 600px);
{
</style>

<div class="lines"></div>