body {
    background-color: #222222;
}

.front img, .back img {
    display: block;
    margin-top: 25px;
    margin-left: auto;
    margin-right: auto;
    width: 50%;
}

.back {
    margin-top: 50px;
    margin-bottom: 25px;
}


@media only screen and (max-width: 576px) { 
    .front img, .back img {
        width: 90%;
    }

    .back {
        margin-top: 25px;
    }
 }

@media only screen and (min-width: 577px) and (max-width: 768px) { 
    .front img, .back img {
        width: 80%;
    }
    
    .back {
        margin-top: 25px;
    }
 }

@media only screen and (min-width: 769px) and (max-width: 1100px) { 
    .front img, .back img {
        width: 70%;
    }
 }