:root { color-scheme: light dark; }
body {
  font: 16px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  max-width: 46rem; margin: 0 auto; padding: 3rem 1.25rem 6rem;
}
h1 { font-size: 1.6rem; margin-bottom: .25rem; }
h2 { font-size: 1.1rem; margin-top: 2rem; }
nav { margin: 2rem 0 3rem; font-size: .9rem; }
nav a { margin-right: 1rem; }
footer { margin-top: 4rem; font-size: .85rem; opacity: .7; }
.todo {
  border: 1px dashed currentColor; border-radius: 6px;
  padding: 1rem 1.25rem; opacity: .75; font-size: .95rem;
}