:root {
  --bg: #f6f4ef;
  --surface: #ffffff;
  --text: #1b2133;
  --muted: #5f6b85;
  --rule: #e2e0d8;
  --accent: #3d4fa3;
  --moon: #e9c97a;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0d1322;
    --surface: #151d31;
    --text: #e8ebf3;
    --muted: #9aa5c0;
    --rule: #26304a;
    --accent: #a9b8ff;
    --moon: #f3dda0;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.65 -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "PingFang TC", "Hiragino Sans", "Noto Sans CJK SC", Roboto, sans-serif;
}
a { color: var(--accent); }
.top {
  max-width: 760px;
  margin: 0 auto;
  padding: 20px 16px 8px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
  justify-content: space-between;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 650;
  font-size: 18px;
  color: var(--text);
  text-decoration: none;
}
.brand .cn { color: var(--muted); font-weight: 500; }
.moon {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  box-shadow: inset -6px -2px 0 0 var(--moon);
  transform: rotate(-20deg);
}
.langs { display: flex; flex-wrap: wrap; gap: 6px; }
.langs button {
  font: inherit;
  font-size: 14px;
  padding: 4px 12px;
  border-radius: 999px;
  border: 1px solid var(--rule);
  background: transparent;
  color: var(--muted);
  cursor: pointer;
}
.langs button[aria-pressed="true"] {
  background: var(--surface);
  color: var(--text);
  border-color: var(--muted);
}
main {
  max-width: 760px;
  margin: 0 auto;
  padding: 8px 16px 64px;
}
article {
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: 20px;
  padding: 28px clamp(18px, 5vw, 44px) 36px;
  overflow-wrap: anywhere;
}
h1 { font-size: 30px; line-height: 1.25; margin: 0 0 4px; }
h2 { font-size: 19px; margin: 32px 0 6px; }
.meta { color: var(--muted); margin: 0 0 20px; font-size: 15px; }
.lead { font-size: 18px; }
ul { padding-left: 1.2em; }
li { margin: 6px 0; }
details {
  border-top: 1px solid var(--rule);
  padding: 12px 0;
}
details:last-of-type { border-bottom: 1px solid var(--rule); }
summary { cursor: pointer; font-weight: 600; }
details p { margin: 8px 0 0; color: var(--muted); }
article.hero {
  text-align: center;
  background: transparent;
  border: 0;
  padding: 48px 8px 8px;
}
.hero h1 { font-size: 36px; }
.hero p { color: var(--muted); max-width: 520px; margin: 12px auto; }
.links { display: flex; justify-content: center; gap: 20px; margin-top: 24px; }