:root {
  --bg: #ffffff;
  --text: #1a1f2b;
  --muted: #5f6878;
  --border: #e4e8ef;
  --accent: #2f6bea;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #12151b;
    --text: #e8ecf2;
    --muted: #9aa3b2;
    --border: #262c37;
    --accent: #6ea0ff;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Noto Sans JP", sans-serif;
  font-size: 16px;
  line-height: 1.75;
  -webkit-text-size-adjust: 100%;
}
main { max-width: 640px; margin: 0 auto; padding: 32px 16px 56px; }
h1 { font-size: 26px; margin: 0 0 8px; line-height: 1.3; }
h2 { font-size: 17px; margin: 32px 0 8px; padding-bottom: 4px; border-bottom: 1px solid var(--border); }
p, ul { margin: 0 0 12px; }
ul { padding-left: 1.3em; }
li { margin-bottom: 4px; }
a { color: var(--accent); overflow-wrap: anywhere; }
code { font-size: 14px; overflow-wrap: anywhere; }
.lead { color: var(--muted); }
.back { margin: 0 0 16px; font-size: 14px; }
.links { margin-top: 32px; }
.date { color: var(--muted); font-size: 14px; }