body {
    font-family: helvetica, sans-serif;
    margin: 0 auto;
    padding: 0 1em;
    max-width: 48em;
}

/* light mode (default) */
body { color: black; background: white; }
a { color: black; } 
hr { border-color: black; }

/* dark mode */
@media (prefers-color-scheme: dark) {
    body { color: white; background: black; }
    a { color: white; } 
    hr { border-color: white; }
}

hr { border-width: 1px; border-style: solid; }
svg { width: 100%; height: 100%; }
code { font-family: courier, monospace; }
ul { padding-left: 1.5em; }
.logo { font-size: 20pt; text-decoration: none; }