:root {
  --fg: #1a1a1a;
  --muted: #555;
  --link: #0a5fb4;
  --rule: #e5e5e5;
  --bg: #fafafa;
}
* { box-sizing: border-box; }
html { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif; }
body { margin: 0; background: var(--bg); color: var(--fg); line-height: 1.55; }
main { max-width: 720px; margin: 0 auto; padding: 3rem 1.5rem 5rem; }
h1 { font-size: 1.9rem; margin: 0.5rem 0 0.25rem; letter-spacing: -0.01em; }
h2 { font-size: 1.15rem; margin: 2rem 0 0.5rem; }
p { margin: 0.5rem 0 0.75rem; }
p.tag { color: var(--muted); margin-top: 0.25rem; }
p.effective { color: var(--muted); font-size: 0.9rem; margin-top: 0; }
a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }
ul { padding-left: 1.25rem; }
li { margin: 0.25rem 0; }
header { padding-bottom: 1rem; border-bottom: 1px solid var(--rule); margin-bottom: 1.5rem; }
section { margin: 2rem 0; }
footer { margin-top: 3rem; padding-top: 1rem; border-top: 1px solid var(--rule); color: var(--muted); font-size: 0.9rem; }