:root {
  --bg: #080F1A;
  --surface: #1A2E4E;
  --text: #F2F4F7;
  --text-muted: #9AA8B8;
  --accent: #6FA8DC;
  --border: rgba(242, 244, 247, 0.1);
  --code-bg: rgba(111, 168, 220, 0.12);
}
* { box-sizing: border-box; }
html { background: var(--bg); }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
}
.container {
  max-width: 760px;
  margin: 0 auto;
  padding: 56px 24px 96px;
}
header.site {
  border-bottom: 1px solid var(--border);
  padding: 24px 24px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 14px;
}
header.site a { color: var(--text-muted); text-decoration: none; }
header.site a:hover { color: var(--accent); }
header.site .brand { color: var(--text); font-weight: 600; letter-spacing: 0.5px; }
header.site nav a { margin-left: 18px; }
h1 { font-size: 32px; font-weight: 700; margin: 0 0 8px; line-height: 1.2; }
h2 { font-size: 22px; font-weight: 600; margin: 40px 0 12px; line-height: 1.3; color: var(--text); }
h3 { font-size: 17px; font-weight: 600; margin: 24px 0 8px; color: var(--text); }
h4 { font-size: 15px; font-weight: 600; margin: 16px 0 8px; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.4px; }
p { margin: 0 0 16px; color: var(--text); }
a { color: var(--accent); text-decoration: underline; text-underline-offset: 2px; }
a:hover { text-decoration: none; }
ul, ol { margin: 0 0 16px; padding-left: 22px; }
li { margin-bottom: 6px; }
blockquote {
  margin: 16px 0;
  padding: 12px 18px;
  border-left: 3px solid var(--accent);
  background: var(--code-bg);
  color: var(--text);
  border-radius: 0 6px 6px 0;
}
code {
  background: var(--code-bg);
  padding: 2px 6px;
  border-radius: 4px;
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  font-size: 0.92em;
  color: var(--accent);
}
hr { border: 0; border-top: 1px solid var(--border); margin: 32px 0; }
table { width: 100%; border-collapse: collapse; margin: 16px 0; font-size: 14px; }
th, td { padding: 10px 12px; text-align: left; border-bottom: 1px solid var(--border); }
th { background: rgba(111, 168, 220, 0.06); color: var(--text); font-weight: 600; }
strong { color: var(--text); font-weight: 600; }
em { color: var(--text-muted); }
.lead { color: var(--text-muted); margin-bottom: 24px; }
.footer-note {
  margin-top: 64px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
  font-size: 13px;
  color: var(--text-muted);
}
.toc {
  margin-bottom: 48px;
}
.toc h2 { margin-top: 0; }
.toc-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  list-style: none;
  padding: 0;
  margin: 0;
}
.toc-grid li { margin: 0; }
.toc-card {
  display: block;
  padding: 18px 20px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  text-decoration: none;
  color: var(--text);
  transition: border-color 0.15s ease, transform 0.15s ease;
}
.toc-card:hover { border-color: var(--accent); transform: translateY(-1px); text-decoration: none; }
.toc-card .title { font-weight: 600; font-size: 16px; display: block; margin-bottom: 4px; }
.toc-card .desc { font-size: 13px; color: var(--text-muted); }
@media (max-width: 600px) {
  .container { padding: 32px 18px 64px; }
  h1 { font-size: 26px; }
  header.site { padding: 16px 18px; flex-direction: column; gap: 8px; align-items: flex-start; }
  header.site nav a { margin-left: 0; margin-right: 14px; }
  table { display: block; overflow-x: auto; }
}