h1{

}

#promo {
    max-width: 400px;
    margin: 0 auto;
}

img {
    display: block;
    max-width: 100%;
}

/* System Fonts as used by GitHub */
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
}

.center {
    text-align: center;
}

#book {
    transform: rotate(-7deg) skewx(5deg) scale(.8);
    border-radius: 3px;
    box-shadow: -50px 50px 50px rgba(0, 0, 0, 0.5);
    max-height: 400px;
    margin: 0 auto;
    transition: transform 1.2s;
}

#book:hover {
    transform: rotate(0deg) skewx(0deg) scale(.9);
    transition: transform 0.2s;
}

#bookcase{
    margin: 0.6rem;
    text-align: center;
    padding-bottom: 1rem;
}

#buy {
    padding: 1rem 2rem;
    border-radius: 5px;
    text-decoration: none;
    font-size: 1.2rem;
    color: white;
    background: #3f47cb;
    transition: background 0.2s;
}

#buy:hover {
    background: #87001a;
    transition: background 0.2s;
}