Flicker effect

<style>
@keyframes flicker {
0% {
opacity: 0.27861;
}
5% {
opacity: 0.34769;
}
10% {
opacity: 0.23604;
}
15% {
opacity: 0.90626;
}
20% {
opacity: 0.18128;
}
25% {
opacity: 0.83891;
}
30% {
opacity: 0.65583;
}
35% {
opacity: 0.67807;
}
40% {
opacity: 0.26559;
}
45% {
opacity: 0.84693;
}
50% {
opacity: 0.96019;
}
55% {
opacity: 0.08594;
}
60% {
opacity: 0.20313;
}
65% {
opacity: 0.71988;
}
70% {
opacity: 0.53455;
}
75% {
opacity: 0.37288;
}
80% {
opacity: 0.71428;
}
85% {
opacity: 0.70419;
}
90% {
opacity: 0.7003;
}
95% {
opacity: 0.36108;
}
100% {
opacity: 0.24387;
}
}

#wrapper::after {
content: " ";
display: block;
position: absolute;
top: 0;
left: 0;
bottom: 0;
right: 0;
background: rgba(18, 16, 16, 0.1);
opacity: 0;
z-index: 2;
pointer-events: none;
animation: flicker 0.15s infinite;
}
#wrapper::before{
content: " ";
display: block;
position: absolute;
top: 0;
left: 0;
bottom: 0;
right: 0;
background: linear-gradient(rgba(18, 16, 16, 0) 50%, rgba(0, 0, 0, 0.25) 50%), linear-gradient(90deg, rgba(255, 0, 0, 0.06), rgba(0, 255, 0, 0.02), rgba(0, 0, 255, 0.06));
z-index: 2;
background-size: 100% 2px, 3px 100%;
pointer-events: none;
}
</style>