.site-background {
    
        background-image: url('images/bg4.jpg');
        background-image: url('images/bg4.webp');
   
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
}

@media (max-width: 768px) {
    .site-background {
        background-image: url('images/bg4-mobile.webp');
    }
}