body {
    margin: 0;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

a {
    color: blue;
}

header,
main,
footer {
    padding: 6px;
}

header h1 {
    margin: 0;
}

header p {
    margin: 0;
}

#dotnet {
    color: silver;
}

h2 {
    margin: 0;
}

nav {
    background-color: silver;
    margin: 6px 0;
}

nav h2 {
    padding: 6px;
    cursor: pointer;
    font-size: 1.2em;
}

nav h2::before {
    content: "≡ ";
}

nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

nav ul li {
    display: none;
    background-color: silver;
    cursor: pointer;
}

nav ul li.active {
    background-color: grey;
}

nav ul li.active a {
    color: white;
}

nav ul li.visible {
    display: block;
    position: relative;
    padding: 6px;
    border-top: 1px solid silver;
}

nav ul li a {
    text-decoration: none;
    color: black;
    display: block;
}

main {
    padding-bottom: 3em;
    flex: 1;
}

footer {
    background-color: silver;
    text-align: center;
}

footer h2,
footer h3 {
    display: none;
}

footer p {
    margin: 0;
    padding: 6px;
}


#validation ul {
    list-style-type: none;
    padding: 0;
    margin: 0;
}

#validation ul li {
    display: inline-block;
    margin-bottom: 12px;
}

#validation ul li+li::before {
    content: "| ";
    margin: 0 6px;
}



form#contacto label{
    display: block;
}

@media (min-width: 600px) {
    header {
        width: 700px;
        margin: 0 auto;
    }

    nav h2 {
        display: none;
    }

    nav ul {
        width: 700px;
        margin: 0 auto;
    }

    nav ul li,
    nav ul li.visible {
        display: inline-block;
        padding: 6px 12px;
        margin-left: 6px;
        border-top: unset;
    }


    main {
        width: 700px;
        margin: 0 auto;
    }
}