:root {
  color-scheme: light dark;
  --bg: #f4f4f2;
  --paper: #ffffff;
  --text: #202020;
  --muted: #6f6f6f;
  --border: #dedede;
  --link: #2868c7;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121212;
    --paper: #1a1a1a;
    --text: #eeeeee;
    --muted: #a6a6a6;
    --border: #333333;
    --link: #7aa7ff;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Arial, sans-serif;
  font-size: 17px;
  line-height: 1.68;
  letter-spacing: 0;
}

a {
  color: var(--link);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

html[data-lang="en"] [lang="zh-Hans"],
html[data-lang="zh-Hans"] [lang="en"] {
  display: none !important;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  background: color-mix(in srgb, var(--paper) 92%, transparent);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(12px);
}

.topbar-inner,
.page {
  width: min(820px, calc(100% - 40px));
  margin: 0 auto;
}

.topbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 64px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  text-decoration: none;
  font-weight: 700;
}

.brand img {
  width: 32px;
  height: 32px;
  border-radius: 7px;
}

.nav {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 10px;
}

.nav a,
.language-toggle {
  display: inline-flex;
  align-items: center;
  min-height: 36px;
  padding: 6px 10px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--paper);
  color: var(--text);
  font: inherit;
  font-size: 14px;
}

.language-toggle {
  cursor: pointer;
}

.nav a[aria-current="page"] {
  border-color: var(--text);
  font-weight: 700;
}

.page {
  padding: 42px 0 72px;
}

.document {
  background: var(--paper);
  border: 1px solid var(--border);
  padding: clamp(24px, 5vw, 48px);
}

h1 {
  margin: 0 0 24px;
  font-size: clamp(2rem, 6vw, 3.2rem);
  line-height: 1.12;
  letter-spacing: 0;
}

h2 {
  margin: 34px 0 12px;
  font-size: 1.32rem;
  line-height: 1.3;
  letter-spacing: 0;
}

p {
  margin: 0 0 14px;
}

ul {
  margin: 0 0 14px;
  padding-left: 1.2em;
}

li + li {
  margin-top: 8px;
}

.meta {
  color: var(--muted);
  margin-bottom: 28px;
}

.doc-links {
  display: grid;
  gap: 12px;
  margin-top: 28px;
}

.doc-link {
  display: block;
  padding: 18px 20px;
  border: 1px solid var(--border);
  background: var(--paper);
  color: var(--text);
}

.doc-link strong {
  display: block;
  margin-bottom: 4px;
}

.doc-link span {
  color: var(--muted);
}

.footer {
  width: min(820px, calc(100% - 40px));
  margin: 0 auto;
  padding: 26px 0;
  color: var(--muted);
  font-size: 14px;
}

@media (max-width: 720px) {
  body {
    font-size: 16px;
  }

  .topbar-inner,
  .page,
  .footer {
    width: min(100% - 28px, 820px);
  }

  .topbar-inner {
    align-items: flex-start;
    flex-direction: column;
    padding: 12px 0;
  }

  .nav {
    flex-wrap: wrap;
    justify-content: flex-start;
  }
}