*{
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    background: url(../Images/obarjeux_prochainement_D.jpg);
    background-size: 100%;
    background-repeat: no-repeat;
    background-position: center center;
    height: 100vh;

}


@media only screen and (max-width:750px){
    body {
        background: url(../Images/obarjeux_prochainement_M.jpg);
        background-size: 100%;
        background-repeat: no-repeat;
        background-position: center center;
        height: 100vh;
    
    }
}