* {
    box-sizing: border-box;
}

/* Defaults; each page overrides them via <body class="season"> below. */
body {
    --bg: #FFFFFF;
    --fg: #000000;
    --accent: var(--fg);
    --footer: var(--accent);
    --font: Verdana, Arial, Helvetica, sans-serif;

    background-color: var(--bg);
    color: var(--fg);
    font-family: var(--font);
    text-align: center;
}

.spring {
    --accent: #355000;
    --footer: #7A1D70;
}

.summer {
    --accent: #7A5A00;
}

.autumn {
    --fg: #98443A;
    --font: "Courier New", Courier, monospace;
}

.advent {
    --bg: #1C4F03;
    --fg: #FFD8D8;
    --font: "Times New Roman", Times, serif;
}

.xmas {
    --bg: #000000;
    --fg: #FFFFFF;
    --font: "Times New Roman", Times, serif;
}

.winter {
    --fg: #31566A;
}

picture {
    display: block;
}

picture > img {
    display: block;
    margin-inline: auto;
}

img {
    max-width: 100%;
    height: auto;
}

h1 {
    margin: 0;
    padding: 10px;
    color: var(--accent);
    font-size: 2.2rem;
    font-weight: bold;
}

.autumn h1,
.advent h1 {
    font-style: oblique;
}

.picture {
    display: block;
    margin: 20px auto 0;
    width: min(50%, 640px);
}

.advent .picture,
.xmas .picture {
    width: auto;
    margin: 50px auto 0;
}

.autumn-content {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    align-items: start;
    gap: 20px;
    max-width: 1100px;
    margin: 20px auto;
}

.poem {
    margin: 0;
    padding: 10px;
    line-height: 2;
}

.poem blockquote {
    margin: 0;
}

.poem figcaption {
    margin-block: 1em;
}

.poem cite {
    font-style: normal;
}

footer {
    padding: 10px;
    text-align: center;
    font-size: 1.25rem;
    font-weight: bold;
    color: var(--footer);
}

footer nav {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 8px 16px;
    margin-bottom: 12px;
    font-size: 1rem;
}

footer a {
    color: inherit;
}

footer p {
    margin: 0;
}

@media (max-width: 700px) {
    .picture {
        width: min(100%, 640px);
    }

    .autumn-content {
        grid-template-columns: minmax(0, 1fr);
    }

    h1 {
        font-size: clamp(1.75rem, 8vw, 2.2rem);
    }
}