:root {
  color-scheme: light dark;
  --ink: #1a1614;
  --muted: rgba(26, 22, 20, 0.65);
  --bg: #ffffff;
  --line: rgba(26, 22, 20, 0.16);
}

@media (prefers-color-scheme: dark) {
  :root {
    --ink: #cccccc;
    --muted: #9d9d9d;
    --bg: #1f1f1f;
    --line: #454545;
  }
}

body {
  margin: 0;
  font: 15px/1.7 -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans", "Noto Sans JP", sans-serif;
  color: var(--ink);
  background: var(--bg);
}

main {
  max-width: 720px;
  margin: 0 auto;
  padding: 32px 20px 64px;
}

h1 {
  font-size: 22px;
  margin: 24px 0 4px;
}

h2 {
  font-size: 15px;
  margin: 20px 0 4px;
}

.meta,
.nav {
  font-size: 13px;
  color: var(--muted);
}

a {
  color: inherit;
}

hr {
  margin: 40px 0;
  border: 0;
  border-top: 1px solid var(--line);
}

li {
  margin: 6px 0;
}

/* 上の行：ロゴと言語メニュー（LP と同じ details） */
.top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 13px;
  color: var(--muted);
}

.top .brand {
  text-decoration: none;
}

.lang {
  position: relative;
}

.lang summary {
  list-style: none;
  cursor: pointer;
  user-select: none;
}

.lang summary::-webkit-details-marker {
  display: none;
}

.lang summary::after {
  content: "";
  display: inline-block;
  width: 6px;
  height: 6px;
  margin: 0 0 3px 7px;
  border: solid currentColor;
  border-width: 0 1.5px 1.5px 0;
  transform: rotate(45deg);
}

.lang[open] summary,
.lang summary:hover,
.top .brand:hover {
  color: var(--ink);
}

.lang ul {
  position: absolute;
  right: 0;
  top: calc(100% + 8px);
  z-index: 1;
  min-width: 120px;
  margin: 0;
  padding: 6px;
  list-style: none;
  color: var(--ink);
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 10px;
}

.lang li {
  margin: 0;
}

.lang li a {
  display: block;
  padding: 6px 10px;
  border-radius: 6px;
  text-decoration: none;
}

.lang li a:hover {
  background: color-mix(in srgb, var(--ink) 8%, transparent);
}

dt {
  font-weight: 600;
}

dd {
  margin: 0 0 10px;
}