:root {
    color-scheme: light dark;
}
body {
    margin: 40px auto;
    max-width: 650px;
    line-height: 1.5;
    font-size: 18px;
    padding: 0 10px;
    color: #111;
    background-color: #fdfdfd;
}
@media (prefers-color-scheme: dark) {
    body {
    color: #eee;
    background-color: #111;
    }
}
h1, h2, h3 {
    line-height: 1.2;
}