selector::before{
content: "";
position: absolute;
top: 50%;
left: 50%;
width: 100%;
height: 100%;
transform: translate(-50%, -50%);
background: url("A URL DA IMAGEM AQUI");
background-position: center;
filter: blur(60px) saturate(2) brightness(1.5);
pointer-events: none;
animation: animate 5s ease infinite;
background-size: cover;
border-radius: 40px;
will-change: filter, background-position; 
z-index: -1;
}

@media(max-width: 767px){
selector::before{
filter: blur(40px) saturate(2) brightness(1.5);
} 
}
 @keyframes animate {
 0% {
 background-size: 100%;
 }

 50% {
 background-size: 500%;
 }

 100% {
 background-size: 100%;
 }
 }