:root {
  color-scheme: light;
  --bg: #f7f9fc;
  --ink: #101828;
  --muted: #5f6b7a;
  --line: #d8e0ea;
  --brand: #2563eb;
  --brand-dark: #1d4ed8;
  --soft: #eef4ff;
  --ok: #067647;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.72;
}

a { color: var(--brand); text-decoration: none; }
a:hover { text-decoration: underline; }

.wrap {
  width: min(1040px, calc(100% - 32px));
  margin: 0 auto;
}

.top {
  border-bottom: 1px solid var(--line);
  background: rgba(255, 255, 255, .92);
  position: sticky;
  top: 0;
  backdrop-filter: blur(10px);
}

.nav {
  min-height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.brand {
  font-weight: 750;
  color: var(--ink);
  letter-spacing: .01em;
}

.nav-links {
  display: flex;
  gap: 18px;
  align-items: center;
  font-size: 14px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 16px;
  border-radius: 8px;
  background: var(--brand);
  color: #fff;
  font-weight: 650;
  border: 1px solid var(--brand);
}

.btn:hover {
  background: var(--brand-dark);
  text-decoration: none;
}

.btn.secondary {
  background: #fff;
  color: var(--brand);
}

.hero {
  padding: 72px 0 42px;
  background: linear-gradient(180deg, #ffffff 0%, #f7f9fc 100%);
}

.eyebrow {
  display: inline-flex;
  padding: 4px 10px;
  border-radius: 999px;
  background: var(--soft);
  color: var(--brand-dark);
  font-size: 13px;
  font-weight: 650;
  margin-bottom: 18px;
}

h1 {
  margin: 0;
  max-width: 850px;
  font-size: 44px;
  line-height: 1.18;
  letter-spacing: 0;
}

.lead {
  max-width: 760px;
  margin: 18px 0 0;
  color: var(--muted);
  font-size: 18px;
}

.actions {
  display: flex;
  gap: 12px;
  margin-top: 28px;
  flex-wrap: wrap;
}

.grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin: 34px 0;
}

.card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 22px;
}

.card h3 {
  margin: 0 0 8px;
  font-size: 18px;
}

.card p { margin: 0; color: var(--muted); font-size: 14px; }

.main {
  padding: 34px 0 72px;
}

article {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 34px;
}

h2 {
  margin: 34px 0 12px;
  font-size: 26px;
  line-height: 1.3;
}

h2:first-child { margin-top: 0; }
h3 { margin: 24px 0 8px; }
p { margin: 10px 0; }
ul, ol { padding-left: 22px; }

code, pre {
  font-family: ui-monospace, SFMono-Regular, Consolas, "Liberation Mono", monospace;
}

code {
  background: #eef2f7;
  padding: 2px 6px;
  border-radius: 5px;
}

pre {
  overflow-x: auto;
  background: #101828;
  color: #f8fafc;
  border-radius: 8px;
  padding: 18px;
  line-height: 1.6;
}

pre code {
  background: transparent;
  padding: 0;
  color: inherit;
}

.note {
  border-left: 4px solid var(--brand);
  background: var(--soft);
  padding: 14px 16px;
  border-radius: 6px;
  color: #1e3a8a;
}

.toc {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin: 24px 0 0;
}

.toc a {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 8px 12px;
  color: var(--ink);
  font-size: 14px;
}

.footer {
  padding: 34px 0;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 13px;
}

@media (max-width: 760px) {
  .nav { align-items: flex-start; flex-direction: column; padding: 14px 0; }
  .nav-links { flex-wrap: wrap; gap: 12px; }
  h1 { font-size: 32px; }
  .lead { font-size: 16px; }
  .grid { grid-template-columns: 1fr; }
  article { padding: 22px; }
}