:root {
  --bg: #fbfaf7;
  --surface: #ffffff;
  --text: #1d2330;
  --muted: #5b6474;
  --line: #e3e0d8;
  --accent: #5b3fa0;
  --accent-soft: #efeaf8;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14161b;
    --surface: #1c1f26;
    --text: #e8e6e1;
    --muted: #a3a9b5;
    --line: #2e323b;
    --accent: #b7a2f0;
    --accent-soft: #2a2438;
    color-scheme: dark;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Hiragino Sans", "Noto Sans JP", "Yu Gothic UI", sans-serif;
  line-height: 1.8;
  overflow-wrap: anywhere;
}
a { color: var(--accent); }
header, main, footer { max-width: 760px; margin: 0 auto; padding: 0 16px; }
header { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding-top: 24px; padding-bottom: 8px; }
.brand { font-weight: 700; font-size: 1.15rem; letter-spacing: .02em; color: var(--text); text-decoration: none; }
.brand span { color: var(--accent); }
nav a { color: var(--muted); text-decoration: none; margin-left: 16px; font-size: .95rem; }
nav a:hover { color: var(--text); }
h1 { font-size: clamp(1.6rem, 5vw, 2.2rem); line-height: 1.4; margin: 40px 0 12px; }
h2 { font-size: 1.25rem; margin: 40px 0 8px; padding-top: 8px; border-top: 1px solid var(--line); }
h3 { font-size: 1.05rem; margin: 24px 0 4px; }
.lead { color: var(--muted); font-size: 1.05rem; margin: 0 0 24px; }
.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 h3 { margin-top: 0; }
.card p { margin: 0; color: var(--muted); font-size: .95rem; }
.note { background: var(--accent-soft); border-radius: 12px; padding: 12px 16px; margin: 16px 0; }
table { width: 100%; border-collapse: collapse; margin: 12px 0; font-size: .95rem; }
th, td { text-align: left; vertical-align: top; padding: 8px; border-bottom: 1px solid var(--line); }
th { width: 30%; color: var(--muted); font-weight: 600; }
.table-wrap { overflow-x: auto; }
ul, ol { padding-left: 1.4em; }
.meta { color: var(--muted); font-size: .9rem; }
blockquote { margin: 12px 0; padding: 8px 16px; border-left: 3px solid var(--accent); background: var(--surface); }
footer { margin-top: 56px; padding-top: 16px; padding-bottom: 40px; border-top: 1px solid var(--line); color: var(--muted); font-size: .9rem; }
footer a { color: var(--muted); }