.centrado {
    text-align:center;
}

.autosize {
    position: relative;
    width: 9%;
    top: 3px;
    left: -2px;
    height: 39px;
}

body {
    background-image:url(../Images/fondo.png);
    background-repeat:no-repeat;
    background-position:center;
    background-attachment: fixed;
    background-size:cover;
}