body {
    background-color: #c0c0cf;
    color: black;
    margin: 0;
    padding: 0;
}

article {
    border: 1px solid black;
    margin: 1em;
    padding: 1em;
}

.nav {
    position: sticky;
    top: 0;
    background-color: #c0c0cf;
    border-bottom: 1px solid black;
    padding: 1em;
}
.nav > menu {
    display: flex;
    list-style: none;
    margin: 0;
    padding: 0;
}

.nav > menu > li {
    margin: 0;
    margin-right: 1em;
}

h1 {
    font-size: x-large;
}

h2 {
    font-size: large;
}

header > :first-child {
    margin-top: 0;
}
section > :last-child {
    margin-bottom: 0;
}