body {
        background-color: #ccc;
        color:#111;
        padding: 0.75em;
}
main {
        margin: 1em auto;
        padding: 0.75em;
        background-color: #eee;
        border-radius:1em;
        max-width: 480px;
}
p {
        padding-left: 1em;
        text-indent: -1em;
}
p:first-of-type { margin-top: 0; }
p:last-of-type { margin-bottom: 0; }
.red   { color: #700; }
.green { color: #070; }

@media (prefers-color-scheme: dark) {
        body {
                background-color: #333333;
                color: #ddd;
        }
        main {
                background-color: #111; 
        }
        .red   { color: #d66; }
        .green { color: #6d6; }
}