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

body{
    background:#d9c2a3;

    height:100vh;

    display:flex;
    justify-content:center;
    align-items:center;

    font-family:'Poppins', sans-serif;

    overflow:hidden;
}

/* ================= LIBRO ================= */

.book{
    position:relative;

    width:350px;
    height:500px;

    perspective:2500px;
}

/* ================= PAGINAS ================= */

.page{
    position:absolute;

    width:100%;
    height:100%;

    transform-style:preserve-3d;

    transform-origin:left;

    transition:1.2s;

    cursor:pointer;
}

/* EFECTO */

.book:hover .page:nth-child(1){
    transform:rotateY(-160deg);
}

.book:hover .page:nth-child(2){
    transform:rotateY(-150deg);
    transition-delay:.2s;
}

.book:hover .page:nth-child(3){
    transform:rotateY(-140deg);
    transition-delay:.4s;
}

/* ================= CARAS ================= */

.front,
.back{
    position:absolute;

    width:100%;
    height:100%;

    backface-visibility:hidden;

    background:white;

    border-radius:15px;

    overflow:hidden;

    box-shadow:0 15px 30px rgba(0,0,0,0.2);

    display:flex;
    flex-direction:column;
    justify-content:center;
    align-items:center;

    padding:20px;
}

/* ATRAS */

.back{
    transform:rotateY(180deg);
}

/* ================= PORTADA ================= */

.portada{
    background:linear-gradient(
        to bottom,
        #5a3d28,
        #8B5E3C
    );

    color:white;
}

.portada h1{
    font-size:45px;
    margin-bottom:20px;
}

.portada p{
    text-align:center;
    line-height:1.6;
}

/* ================= IMAGENES ================= */

.front img,
.back img{
    width:100%;
    height:300px;

    object-fit:cover;

    border-radius:12px;

    margin-bottom:20px;
}

/* ================= TITULOS ================= */

.front h2,
.back h2{
    color:#5C4033;
}

/* ================= CONTACTO ================= */

.contacto{
    background:#F2ECE6;
}

.contacto h1{
    color:#5C4033;
    margin-bottom:20px;
}

.contacto a{
    text-decoration:none;

    background:#8B5E3C;
    color:white;

    padding:12px 25px;

    border-radius:10px;

    transition:.3s;
}

.contacto a:hover{
    background:#5C4033;
}

/* ================= RESPONSIVE ================= */

@media(max-width:768px){

    .book{
        width:280px;
        height:420px;
    }

    .front img,
    .back img{
        height:220px;
    }

    .portada h1{
        font-size:35px;
    }
}