:root {
  --bg: #fbfaf7;
  --surface: #ffffff;
  --ink: #1b1d2a;
  --muted: #555a6e;
  --line: #e4e1d8;
  --accent: #b3261e;
  --accent-ink: #ffffff;
  --link: #1f4fbf;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #151728;
    --surface: #1d2036;
    --ink: #eceaf4;
    --muted: #aeb1c4;
    --line: #2f3350;
    --accent: #ff7a6b;
    --accent-ink: #151728;
    --link: #9cb8ff;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 1.0625rem/1.65 -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Segoe UI", "Noto Sans JP", system-ui, sans-serif;
}
a { color: var(--link); text-underline-offset: 0.15em; }
a:focus-visible { outline: 3px solid var(--link); outline-offset: 2px; border-radius: 2px; }
.skip { position: absolute; left: -999px; }
.skip:focus { left: 1rem; top: 1rem; background: var(--surface); padding: .5rem .75rem; z-index: 10; }
header.site {
  border-bottom: 1px solid var(--line);
  background: var(--surface);
}
header.site .wrap { display: flex; align-items: center; gap: 1rem; flex-wrap: wrap; padding-block: .9rem; }
.brand { display: flex; align-items: center; gap: .6rem; color: var(--ink); text-decoration: none; font-weight: 700; font-size: 1.15rem; }
.mark { width: 2rem; height: 2rem; border-radius: .5rem; display: block; }
nav.site { margin-left: auto; display: flex; gap: 1.1rem; }
nav.site a { color: var(--muted); text-decoration: none; font-weight: 600; }
nav.site a[aria-current="page"], nav.site a:hover { color: var(--ink); text-decoration: underline; }
.wrap { max-width: 44rem; margin: 0 auto; padding-inline: 1rem; }
main { padding-block: 2rem 3rem; }
h1 { font-size: clamp(1.75rem, 5vw, 2.25rem); line-height: 1.2; margin: 0 0 .5rem; letter-spacing: -0.01em; }
h2 { font-size: 1.3rem; line-height: 1.3; margin: 2.25rem 0 .6rem; padding-top: 1.25rem; border-top: 1px solid var(--line); }
h3 { font-size: 1.05rem; margin: 1.5rem 0 .4rem; }
p, ul, ol { margin: 0 0 1rem; }
li { margin-bottom: .35rem; }
.lede { color: var(--muted); font-size: 1.1rem; }
.meta { color: var(--muted); font-size: .95rem; }
.card {
  background: var(--surface); border: 1px solid var(--line); border-radius: .9rem;
  padding: 1.1rem 1.25rem; margin: 1.25rem 0;
}
.card p:last-child, .card ul:last-child { margin-bottom: 0; }
.summary li { margin-bottom: .5rem; }
.kbd { font-weight: 600; }
footer.site { border-top: 1px solid var(--line); color: var(--muted); font-size: .95rem; }
footer.site .wrap { padding-block: 1.5rem 2.5rem; display: flex; gap: 1.25rem; flex-wrap: wrap; }
footer.site a { color: var(--muted); }