body {

    background-image: url("IMAGENES/fondo.jpg") ;

}

h1 {

    text-align: center;
    font-size: xx-large;
    color: aqua;
}


header {
    background: rgba(0,0,0,0.7);
    width: 100%;
    position: fixed;
    z-index: 100;
}

nav {
    float: left;
}

nav ul {
    list-style: none;
    overflow: hidden; 
}

nav ul li {
    float: left;
    font-family: Arial, Helvetica, sans-serif;;
    font-size: 20px;
}


nav ul li a {
    display: block; 
    padding: 20px;
    color: #fff;
    text-decoration: none;
}

nav ul li:hover {
    background: #2395ec;
}