body:before {
    content: '';
    position: fixed;
    left: 0;
    top: 0;
    width: 100%; 
    height: 100%;
    will-change: transform;
    z-index: -1;
    background-size: cover;
    background-image: url("./background.jpg");
    background-repeat: no-repeat;
}

body {
    position:relative;
    z-index: 0;
}