html, body {
    margin: 0;
    padding: 0;
    top: 0;
    left: 0;
    background: #eee;
    font-family: sans-serif;
    color: #333;
}

section, nav, header, footer {
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
    padding-left: 10px;
    padding-right: 10px;
}

section, nav {
    min-height: 100vh;
    padding-top: 20px;
    display: none;
}

header {
    padding: 10px 0;
    font-weight: bold;
    font-size: 1.3em;
}

header a {
    font-size: 0.8em;
    font-weight: normal;
    margin-left: 15px;
}

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

nav ul li {
    border-bottom: 1px solid #aaa;
    transition: background 0.1s linear;
}

nav ul li:nth-child(1) {
    border-top: 1px solid #aaa;
}

nav ul li:hover {
    background: #f6f6f6;
}

nav ul li a {
    padding: 10px;
    display: block;
    text-decoration: none;
}

:target {
    display: block;
}

footer {
    padding: 20px 0;
    color: #666;
}

@media only screen and (max-width: 768px) {
    section, nav, header, footer {
        max-width: 100%;
    }

    header, footer {
        padding-left: 10px;
        padding-right: 10px;
    }
}