:root {
  --bg: #f7f6f2;
  --surface: #ffffff;
  --text: #1f2328;
  --muted: #5b6168;
  --accent: #2f6f5e;
  --line: #e2dfd8;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #15171a;
    --surface: #1d2024;
    --text: #e8e6e1;
    --muted: #a3a8ae;
    --accent: #7cc4ad;
    --line: #2e3237;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Hiragino Sans", "Noto Sans JP", "Segoe UI", sans-serif;
  line-height: 1.75;
  -webkit-text-size-adjust: 100%;
}
a { color: var(--accent); }
header, main, footer { max-width: 760px; margin: 0 auto; padding: 0 16px; }
header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 20px;
  padding-bottom: 20px;
  gap: 12px;
  flex-wrap: wrap;
}
.brand { font-weight: 700; font-size: 1.15rem; color: var(--text); text-decoration: none; }
nav { display: flex; gap: 16px; flex-wrap: wrap; font-size: 0.95rem; }
nav a { text-decoration: none; }
nav a[aria-current="page"] { color: var(--text); font-weight: 600; }
.hero { padding: 40px 0 24px; }
.hero h1 { font-size: clamp(1.8rem, 6vw, 2.6rem); line-height: 1.3; margin: 0 0 12px; }
.hero p { color: var(--muted); font-size: 1.1rem; margin: 0; }
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(210px, 1fr)); gap: 12px; margin: 24px 0; }
.card { background: var(--surface); border: 1px solid var(--line); border-radius: 12px; padding: 16px; }
.card h2 { font-size: 1rem; margin: 0 0 6px; }
.card p { margin: 0; color: var(--muted); font-size: 0.95rem; }
article h1 { font-size: 1.7rem; line-height: 1.35; margin: 32px 0 4px; }
article h2 { font-size: 1.2rem; margin: 36px 0 8px; padding-top: 12px; border-top: 1px solid var(--line); }
article h3 { font-size: 1.02rem; margin: 20px 0 4px; }
.meta { color: var(--muted); font-size: 0.9rem; margin: 0 0 24px; }
.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: 0.93rem; background: var(--surface); }
th, td { text-align: left; vertical-align: top; padding: 8px 10px; border: 1px solid var(--line); }
th { white-space: nowrap; }
.note { background: var(--surface); border-left: 3px solid var(--accent); padding: 10px 14px; border-radius: 4px; }
footer { color: var(--muted); font-size: 0.88rem; padding-top: 40px; padding-bottom: 32px; }