:root {
    --background: #fefefe;
    --text-color: #454545;
}

@media(prefers-color-scheme: dark) {
    :root {
        --background: #222;
        --text-color: #fefefe;
    }
}

body {
    background: var(--background);
    color: var(--text-color);
    font-size: 18px;
    line-height: 1.6;
    margin: 40px auto;
    max-width: 650px;
    padding: 0 1em;
}

h1, h2, h3 {
    line-height: 1.2;
}

p {
    hyphens: auto;
    text-align: justify;
}

header {
    display: flex;
    justify-content: space-between;
}

nav {
    display: flex;
    align-items: center;
}

nav > div {
    margin-left: 1em;
}