:root {
  color-scheme: light dark;
  --paper: #f8f4e9;
  --ink: #202a31;
  --muted: #4d5b60;
  --accent: #25534d;
  --rule: #a9aca0;
  --inset: #efe9db;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "PingFang TC",
    "Hiragino Sans", "Microsoft YaHei", "Yu Gothic", system-ui, sans-serif;
  line-height: 1.6;
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper: #141e29;
    --ink: #f4efdf;
    --muted: #c0c9c8;
    --accent: #a4dbc8;
    --rule: #626e75;
    --inset: #202d38;
  }
}

:root:lang(zh), :root:lang(ja) { line-height: 1.75; }
* { box-sizing: border-box; }

body {
  max-inline-size: 712px;
  margin: 0 auto;
  padding: clamp(24px, 6vw, 64px) 16px 32px;
  background: var(--paper);
  color: var(--ink);
  overflow-wrap: anywhere;
}

a {
  color: var(--accent);
  text-decoration-thickness: .08em;
  text-underline-offset: .19em;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 4px;
}

.languages, .footer-links {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0 1.25rem;
}

.languages {
  padding-block-end: .75rem;
  border-block-end: 3px double var(--rule);
  font-size: .875rem;
}

.languages a {
  display: inline-flex;
  align-items: center;
  min-block-size: 32px;
}

.languages [aria-current="page"] {
  color: var(--ink);
  font-weight: 700;
}

.masthead {
  display: flex;
  align-items: center;
  gap: .875rem;
  margin-block: 1.65rem;
  font-weight: 700;
}

.masthead img {
  border-radius: 11px;
  flex: none;
}

h1, h2 {
  line-height: 1.22;
  text-wrap: balance;
}

h1 {
  margin: 0;
  font-size: clamp(2rem, 6vw, 3rem);
  letter-spacing: -.025em;
}

h2 {
  margin: 0 0 .6rem;
  font-size: 1.25rem;
}

p { margin: .65rem 0 0; }

.lead { font-size: 1.125rem; }

.date, footer {
  color: var(--muted);
  font-size: .875rem;
}

section { margin-block-start: 2rem; }

.overview {
  padding: 1.125rem 1.25rem;
  border-inline-start: 3px solid var(--accent);
  background: var(--inset);
}

details { border-block-start: 1px solid var(--rule); }
details:last-child { border-block-end: 1px solid var(--rule); }

summary {
  padding-block: .875rem;
  cursor: pointer;
  font-weight: 650;
}

details > div { padding-block-end: 1rem; }
details > div > :first-child { margin-block-start: 0; }

footer {
  margin-block-start: 3rem;
  padding-block-start: 1rem;
  border-block-start: 3px double var(--rule);
}

.footer-links a {
  display: inline-flex;
  align-items: center;
  min-block-size: 28px;
}