body {
    background: url('images/litwin_publishing.jpg');
    background-color: black;
    background-position: center top 80px;
    background-repeat: no-repeat;
    background-size: cover;
    font-family: arial;
    background-attachment: fixed;
    margin: 0;
}

html, body {
    font-size: 16px;
}


header {
    background: black;
    padding: 1rem;
    text-align: center;

}


header a {
    color: white;
    text-decoration: none;
}
h1, h2, h3 {
    font-weight: normal;
    margin: 0;
}

header h1 {
    color: white;
}


.book_download {
    background: red;
    color: white;
    display: inline-block;
    padding: 0.5rem 2rem;
    
    text-decoration: none;
    font-size: 1.5rem;
    border-radius: 0.2rem;
    margin-top: 1rem;
    border: 2px solid white;
}

.book_download:hover {
    background: #bd2a2a;
}


.center {
    text-align: center;
}

.cd {
    width: 100%;
}

.book {
    width: 100%;
}

.img-fluid {
    max-width: 600px;
    width: 100%;
    height: auto;
}

.container {
    padding: 2rem 3rem;
        display: flex;
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: center;
    align-content: center;
     
    box-sizing: border-box;
}

.book_cover {
    width: 49%;
}

.book_covers {
    display: flex;
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: center;
    align-content: center;
    width: 80%;
    margin-top: 2rem;
    margin: 2rem auto;
}

img {
    border: 8px solid black;
    border-radius: 1rem;
    margin-top: 1rem;
}

@media all and (max-width: 767px) {
    .book_cover {
        width: 100%;
    }
    
    .container {
        padding: 2rem;
    }
    
    .book_covers {
        width: 100%;
    }
}