:root {
  --ink: #1b1d1f;
  --muted: #5d6368;
  --rule: #d9dcdf;
  --paper: #fbfbfa;
  --accent: #1f6f78;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root { --ink: #e6e8ea; --muted: #9aa1a7; --rule: #33383c; --paper: #141618; --accent: #6fc1c9; }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 17px/1.6 ui-sans-serif, system-ui, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}
main { max-width: 40rem; margin: 0 auto; padding: 4rem 1rem 5rem; }
header { border-bottom: 1px solid var(--rule); padding-bottom: 1.25rem; margin-bottom: 2rem; }
.mark { font-weight: 600; letter-spacing: 0.01em; color: var(--accent); text-decoration: none; }
h1 { font-size: 1.9rem; line-height: 1.2; margin: 0.6rem 0 0.4rem; font-weight: 650; }
.updated { color: var(--muted); margin: 0; font-size: 0.95rem; }
h2 { font-size: 1.15rem; margin: 2.2rem 0 0.5rem; }
ul, ol { padding-left: 1.2rem; }
li { margin: 0.35rem 0; }
a { color: var(--accent); }
footer { margin-top: 3rem; padding-top: 1.25rem; border-top: 1px solid var(--rule); color: var(--muted); font-size: 0.95rem; }
footer nav { display: flex; gap: 1.25rem; flex-wrap: wrap; }