@media only screen and (max-width: 291px) {
    .book {
        width: 200px;
        height: 290px;
        margin-left: 10px;
        margin-right: 10px;
    }
    body {
        font-size: 18px;
    }
}

@media only screen and (max-width: 310px) {
    .social {
        width: 80%;
        margin-left: 10%;
    }
    .social-icon-link {
        float: none;
    }
    #fb {
        margin: 0;
    }
    #ig {
        margin: 0;
    }
    .social ul {
        height: auto;
    }
}

@media only screen and (max-width: 760px) {
    #back {
        text-align: center;
        width: 20%;
        margin-left: 40%;
    }
}

@media only screen and (max-width: 540px) {
    #logo {
        width: 50%;
        height: auto;
        margin-left: 25%;
    }
    #header-title-div {
        width: 90%;
        margin-left: 5%;
    }
}