:root {
  color-scheme: light dark;
  --bg: #ffffff;
  --fg: #1c1c1e;
  --sub: #6e6e73;
  --line: #d2d2d7;
  --link: #0a66d0;
  --soft: #f5f5f7;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #000000;
    --fg: #f5f5f7;
    --sub: #a1a1a6;
    --line: #38383a;
    --link: #4aa3ff;
    --soft: #1c1c1e;
  }
}
* { box-sizing: border-box; }
html, body { margin: 0; background: var(--bg); color: var(--fg); }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Noto Sans JP", sans-serif;
  line-height: 1.8;
  -webkit-text-size-adjust: 100%;
}
a { color: var(--link); }
header, main, footer { max-width: 720px; margin: 0 auto; padding: 0 16px; }
header { padding-top: 20px; padding-bottom: 8px; }
header a { color: var(--fg); text-decoration: none; font-weight: 700; font-size: 1.1rem; }
.brand { display: inline-flex; align-items: center; gap: 8px; }
.brand img { border-radius: 22%; box-shadow: 0 0 0 1px var(--line); }
.hero-icon { display: block; border-radius: 22%; box-shadow: 0 0 0 1px var(--line), 0 6px 20px rgba(0, 0, 0, 0.12); margin-bottom: 20px; }
main { padding-bottom: 48px; }
h1 { font-size: 1.6rem; line-height: 1.4; margin: 24px 0 8px; }
h2 { font-size: 1.15rem; line-height: 1.5; margin: 36px 0 8px; padding-top: 16px; border-top: 1px solid var(--line); }
h3 { font-size: 1rem; margin: 20px 0 4px; }
p, ul, ol, dl { margin: 8px 0; }
ul, ol { padding-left: 1.4em; }
li { margin: 4px 0; }
.date { color: var(--sub); font-size: 0.9rem; margin: 0 0 16px; }
table { width: 100%; border-collapse: collapse; margin: 16px 0; }
th, td { text-align: left; vertical-align: top; padding: 12px 8px; border-bottom: 1px solid var(--line); }
th { width: 32%; font-weight: 600; }
footer { border-top: 1px solid var(--line); padding-top: 16px; padding-bottom: 32px; color: var(--sub); font-size: 0.9rem; }
footer nav { display: flex; flex-wrap: wrap; gap: 4px 16px; margin-bottom: 8px; }
footer a { color: var(--sub); }
.hero { padding: 40px 0 8px; }
.hero h1 { font-size: 2.2rem; margin: 0 0 12px; }
.hero p { font-size: 1.05rem; }
.box { background: var(--soft); border-radius: 12px; padding: 16px; margin: 16px 0; }
@media (max-width: 480px) {
  th, td { display: block; width: 100%; padding: 4px 0; border: none; }
  th { padding-top: 12px; }
  tr { display: block; border-bottom: 1px solid var(--line); padding-bottom: 8px; }
}