:root {
  --bg: #ffffff;
  --fg: #1d1d1f;
  --muted: #5f6368;
  --line: #e5e7eb;
  --accent: #2f5bea;
  --soft: #f5f7fb;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111214;
    --fg: #f2f2f3;
    --muted: #a3a8b0;
    --line: #2a2d33;
    --accent: #7c9bff;
    --soft: #1a1c20;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Noto Sans JP", "Segoe UI", sans-serif;
  line-height: 1.75;
}
a { color: var(--accent); }
.wrap { max-width: 880px; margin: 0 auto; padding: 0 20px; }
header.site { border-bottom: 1px solid var(--line); }
header.site .wrap { display: flex; align-items: center; justify-content: space-between; min-height: 64px; flex-wrap: wrap; gap: 8px; }
.logo { font-weight: 700; font-size: 20px; letter-spacing: .02em; color: var(--fg); text-decoration: none; }
nav a { margin-left: 16px; color: var(--muted); text-decoration: none; font-size: 14px; }
nav a:hover { color: var(--fg); }
.hero { padding: 72px 0 56px; }
.hero h1 { font-size: clamp(28px, 5vw, 42px); line-height: 1.3; margin: 0 0 16px; }
.hero p { color: var(--muted); font-size: 17px; max-width: 640px; margin: 0; }
section { padding: 40px 0; border-top: 1px solid var(--line); }
section h2 { font-size: 22px; margin: 0 0 16px; }
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 16px; }
.card { background: var(--soft); border-radius: 12px; padding: 20px; }
.card h3 { margin: 0 0 8px; font-size: 17px; }
.card p { margin: 0; color: var(--muted); font-size: 15px; }
ul.points { padding-left: 1.2em; margin: 0; }
ul.points li { margin-bottom: 6px; }
dl.info { display: grid; grid-template-columns: 9em 1fr; gap: 10px 16px; margin: 0; }
dl.info dt { color: var(--muted); }
dl.info dd { margin: 0; }
.doc { padding: 40px 0 56px; }
.doc h1 { font-size: 28px; margin: 0 0 8px; }
.doc h2 { font-size: 18px; margin-top: 32px; }
.doc .meta { color: var(--muted); font-size: 14px; }
footer.site { border-top: 1px solid var(--line); padding: 28px 0; color: var(--muted); font-size: 13px; }
footer.site a { color: var(--muted); margin-right: 16px; }
@media (max-width: 560px) {
  dl.info { grid-template-columns: 1fr; gap: 2px; }
  dl.info dd { margin-bottom: 10px; }
  nav a { margin-left: 0; margin-right: 12px; }
}