:root {
  --bg: #ffffff;
  --fg: #0a0a0a;
  --muted: #5a5a5a;
  --line: #e6e6e6;
  --accent: #111111;
  --accent2: #0066ff;
}
html, body { height: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.7;
}
.hero {
  border-bottom: 1px solid var(--line);
  padding: 40px 20px;
  position: sticky; top: 0; background: var(--bg); z-index: 10;
}
.hero-inner { max-width: 1100px; margin: 0 auto; display: flex; align-items: center; justify-content: space-between; gap: 16px; }
.brand { display: flex; align-items: center; gap: 12px; }
.logo img { height: 36px; }
.title { font-weight: 700; font-size: 20px; letter-spacing: 0.2px; }
.subtitle { color: var(--muted); font-size: 14px; }
.container { max-width: 1100px; margin: 0 auto; padding: 24px 20px 80px; display: grid; grid-template-columns: 260px 1fr; gap: 32px; }
@media (max-width: 980px){ .container { grid-template-columns: 1fr; } .toc { position: static; top: auto; } }

/* TOC */
.toc { position: sticky; top: 96px; align-self: start; border: 1px solid var(--line); border-radius: 12px; padding: 16px; }
.toc h3 { margin: 0 0 8px; font-size: 14px; text-transform: uppercase; letter-spacing: 0.08em; }
.toc a { display: block; color: var(--fg); text-decoration: none; padding: 6px 8px; border-radius: 8px; font-size: 14px; }
.toc a:hover { background: #f4f7ff; color: var(--accent2); }
.toc .lvl1 { font-weight: 600; margin-top: 6px; }
.toc .lvl2 { margin-left: 12px; color: var(--muted); }

/* Content */
article h1 { font-size: 36px; margin: 0.6em 0; }
article h2 { font-size: 24px; margin: 1.6em 0 0.6em; padding-bottom: 6px; border-bottom: 2px solid var(--line); }
article h3 { font-size: 18px; margin: 1.2em 0 0.4em; }
article p, article li { font-size: 16px; }
article code { background: #f3f3f3; padding: 2px 6px; border-radius: 6px; font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace; font-size: 0.95em; }
article pre { background: #f8f8f8; border: 1px solid var(--line); padding: 16px; border-radius: 12px; overflow-x: auto; font-size: 14px; }
.callout { border-left: 4px solid var(--accent2); background: #f6faff; padding: 12px 14px; border-radius: 8px; }
.foot { color: var(--muted); text-align: center; border-top: 1px solid var(--line); padding: 32px 0 16px; margin-top: 56px; }
.badge { display: inline-block; font-size: 12px; border: 1px solid var(--line); padding: 4px 8px; border-radius: 999px; background: #fafafa; }
a { color: var(--accent2); }

/* Mobile layout fixes: stack TOC above content, no overlap */
@media (max-width: 980px) {
  .container {
    display: block;
    padding: 16px 16px 64px;
  }
  .toc {
    position: relative;
    top: 0;
    z-index: 0;
    margin: 0 0 16px 0;
    border: 0;
    border-bottom: 1px solid var(--line);
    border-radius: 0;
  }
  .toc a {
    display: inline-block;
    margin-right: 8px;
    padding: 6px 8px;
  }
  article {
    margin-top: 12px;
  }
  .hero-inner {
    flex-wrap: wrap;
    row-gap: 8px;
  }
  .logo img {
    max-height: 28px;
  }
}