:root {
  --bg: #ffffff;
  --fg: #1c1e21;
  --muted: #5c6670;
  --accent: #2563eb;
  --border: #e6e8eb;
  --code-bg: #f5f7fa;
  --sidebar-bg: #fafbfc;
  --max: 1180px;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  color: var(--fg);
  background: var(--bg);
}

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

header.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 12px 24px;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(180%) blur(8px);
  border-bottom: 1px solid var(--border);
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 17px;
  color: var(--fg);
}
.brand .mark {
  width: 26px; height: 26px;
  border-radius: 7px;
  background: linear-gradient(135deg, #2563eb, #7c3aed);
  display: inline-block;
}
.topbar nav { margin-left: auto; display: flex; gap: 20px; font-size: 15px; }
.topbar nav a { color: var(--muted); }

.layout {
  display: grid;
  grid-template-columns: 240px minmax(0, 1fr);
  gap: 40px;
  max-width: var(--max);
  margin: 0 auto;
  padding: 32px 24px 80px;
}

aside.sidebar {
  position: sticky;
  top: 70px;
  align-self: start;
  height: max-content;
  background: var(--sidebar-bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 18px 16px;
}
aside.sidebar h4 {
  margin: 14px 8px 6px;
  font-size: 12px;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: var(--muted);
}
aside.sidebar ul { list-style: none; margin: 0 0 8px; padding: 0; }
aside.sidebar li a {
  display: block;
  padding: 6px 10px;
  border-radius: 7px;
  color: var(--fg);
  font-size: 14.5px;
}
aside.sidebar li a:hover { background: #eef1f5; text-decoration: none; }
aside.sidebar li a.active { background: #e7effe; color: var(--accent); font-weight: 600; }

main.content { min-width: 0; }
main.content h1 { font-size: 30px; margin: 0 0 8px; letter-spacing: -.01em; }
main.content h2 { font-size: 21px; margin: 34px 0 10px; padding-top: 6px; }
main.content h3 { font-size: 17px; margin: 24px 0 8px; }
main.content p { margin: 12px 0; }
.lead { font-size: 18px; color: var(--muted); margin-top: 0; }

code {
  font-family: "SF Mono", "JetBrains Mono", Menlo, Consolas, monospace;
  font-size: 13.5px;
  background: var(--code-bg);
  padding: 2px 6px;
  border-radius: 5px;
}
pre {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 16px 18px;
  overflow-x: auto;
  font-size: 13.5px;
  line-height: 1.55;
}
pre code { background: none; padding: 0; }

table { border-collapse: collapse; width: 100%; margin: 16px 0; font-size: 14.5px; }
th, td { text-align: left; padding: 9px 12px; border-bottom: 1px solid var(--border); }
th { color: var(--muted); font-weight: 600; }

.note {
  border-left: 3px solid var(--accent);
  background: #f3f7ff;
  padding: 12px 16px;
  border-radius: 0 8px 8px 0;
  margin: 18px 0;
}

.pager {
  display: flex;
  justify-content: space-between;
  margin-top: 48px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
  font-size: 15px;
}

footer.site {
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 13.5px;
  text-align: center;
  padding: 22px;
}

.kbd {
  font-family: monospace;
  font-size: 12px;
  border: 1px solid var(--border);
  border-bottom-width: 2px;
  border-radius: 5px;
  padding: 1px 6px;
  background: #fff;
}

@media (max-width: 820px) {
  .layout { grid-template-columns: 1fr; }
  aside.sidebar { position: static; }
}