body {
    background-image: url("img/fondo.jpg");
}

h2 {
    border-bottom: solid black 2px;
    margin: 0 0 20px 0;
}

table {
    max-width: 90%;
    margin: auto;
}

.contenido {
    background-color: aliceblue;
    width: 80%;
    margin: 0 10%;
    min-height: 90vh;
}

form {
    padding: 20px;
    border-top: solid black 2px;
    border-bottom: solid black 2px;
}