body{
            margin:0;
            background-color: #000;
            text-align: justify;
            width: 1200px;
            margin-left: auto;
            margin-right: auto;
        }
        
        *{
            box-sizing: border-box;
        }
        
        .total{
            width: 1200px;
        }

        .book-section{
            height: 100vh;
            width: 100%;
            padding: 40px 0;
            text-align: center;
        }
        /*---  TAMAÑO DEL LIBRO (LAS DOS HOJAS JUNTAS) ---*/
        .book-section > .container{ 
            height: 800px;
            width: 1100px;
            position: relative;
            left: 50%;
            transform: translateX(-50%);
            border-radius: 2%;
            margin-bottom: 30px;
            perspective: 1200px;
        }
        /*--  ALTO DE LA HOJA  ----*/
        .container > .right{
            position: absolute;
            height: 100%;
            width: 50%;
            transition: 0.7s ease-in-out;
            transform-style: preserve-3d;
        }

        .book-section > .container > .right{
            right:0;
            transform-origin: left;
            border-radius: 10px 0 0 10px;
        }

        /*---  ALTO DE LA IMAGEN DENTRO DE LA HOJA  ----*/
        .right > figure.front, .right > figure.back{
            margin: 0;
            height: 100%;
            width: 100%;
            position: absolute;
            left:0;
            top:0;
            background-size: 100%; /* ESTO DA EL TAMAÑO INTERNO DE LA HOJA */
            background-repeat: no-repeat;
            backface-visibility: hidden;
            background-color: white;
            overflow: hidden;
        }


        .right > figure.front{
            background-position: right;
            border-radius: 0 0px 0px 0;
            box-shadow: 2px 2px 15px -2px rgba(0,0,0,0.2);
        }
        .right > figure.back{
            background-position: left;
            border-radius: 10px 0 0 10px;
            box-shadow: -2px 2px 15px -2px rgba(0,0,0,0.2);
            transform: rotateY(180deg);
        }
        .flip{
            transform: rotateY(-180deg);
        }

        .flip::before{
            content: "";
            position: absolute;
            top:0;
            left:0;
            z-index: 10;
            width: 100%;
            height: 100%;
            border-radius: 0 10px 10px 0;
            background-color: rgba(0,0,0,0.1);
        }

        .book-section > button{
            border: 2px solid #ef9f00;
            background-color: transparent;
            color: #ef9f00;
            color: #ef9f00;
            padding: 10px 20px;
            border-radius: 5px;
            cursor: pointer;
            margin: 10px;
            transition: 0.3s ease-in-out;
        }
        .book-section > button:focus, .book-section > button:active{
            outline: none;
        }

        /*---  LETRA TITULO PAGINA  ---*/
        .book-section > p{
            color: rgba(0,0,0,0.7);
            font-family: calibri;
            font-size: 24px;
        }
        .book-section > p > a{
            text-decoration: none;
            color: #ef9f00;
        }
        .book-section > button:hover{
            background-color: #ef9f00;
            color: #fff;
        }

        /*---  LA PORTADA DEL LIBRO   ---*/
        .front#cover, .back#back-cover{
            background-color: #fff;
            font-family: calibri;
            text-align: left;
            padding: 0 30px;
        }
        .front#cover h1{
            color: #fff;
        }
        .front#cover p{
            color: rgba(0,0,0,0.8);
            font-size: 14px;
        }