:root {
  --bg: #fbfbfa;
  --fg: #1f2328;
  --muted: #59636e;
  --accent: #0b6bcb;
  --rule: #d8dee4;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #15181c;
    --fg: #e6e9ec;
    --muted: #9aa4ae;
    --accent: #6cb6ff;
    --rule: #30363d;
    color-scheme: dark;
  }
}

* {
  box-sizing: border-box;
}

html {
  font-size: 100%;
}

body {
  margin: 0;
  padding: 3rem 1rem 4rem;
  background: var(--bg);
  color: var(--fg);
  font-family: system-ui, -apple-system, "Segoe UI", "Hiragino Sans", "Noto Sans JP", sans-serif;
  line-height: 1.7;
}

main {
  max-width: 40rem;
  margin: 0 auto;
}

header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 2.5rem;
}

h1 {
  margin: 0;
  font-size: 2rem;
  letter-spacing: -0.01em;
}

h1 small {
  display: block;
  font-size: 1rem;
  font-weight: normal;
  color: var(--muted);
}

h2 {
  margin: 2.5rem 0 0.75rem;
  padding-bottom: 0.25rem;
  border-bottom: 1px solid var(--rule);
  font-size: 1.1rem;
}

p,
ul {
  margin: 0 0 1rem;
}

ul {
  padding-left: 1.25rem;
}

li + li {
  margin-top: 0.25rem;
}

a {
  color: var(--accent);
  text-underline-offset: 0.15em;
}

.lang {
  font-size: 0.9rem;
  white-space: nowrap;
}

.lang [aria-current] {
  color: var(--muted);
  font-weight: bold;
}

.note {
  color: var(--muted);
}

footer {
  margin-top: 3rem;
  font-size: 0.85rem;
  color: var(--muted);
}