html, body {
    padding: 0;
    margin: 0;
    font-family: sans-serif;
}

body > main {
    width: 650px;
    min-height: 500px;
    padding: 1rem;
}

h1, h2, h3, h4, h5, h6 {
    font-family: serif;
}

#main-nav {
    list-style: none;
    padding: 0;
    display: flex;
    justify-content: space-between;
    width: 644px;
}