body{
    background: url("../Imagenes/01.jpg")  fixed center; 
}
button{
    background-color: lightslategray;
    font-size: 15px;
    border-bottom-color: black;
    margin-bottom: auto;
}
.gris {color: dimgrey;    
}
.blanco{color: white;    
}    
.naranja{color: orangered;
}
.verde{color:forestgreen;
}