:root {
  --bg: #ffffff;
  --bg-soft: #f6f8fa;
  --bg-code: #f6f8fa;
  --border: #e3e8ee;
  --text: #1f2933;
  --text-soft: #5b6775;
  --accent: #2563eb;
  --accent-soft: #e8efff;
  --danger: #dc2626;
  --sidebar-w: 240px;
  --topbar-h: 56px;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto, Helvetica, Arial, sans-serif;

  /* syntax */
  --syn-comment: #6a737d;
  --syn-key: #0550ae;
  --syn-string: #0a7a3d;
  --syn-keyword: #a626a4;
  --syn-number: #b45309;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f172a;
    --bg-soft: #131c31;
    --bg-code: #111a2e;
    --border: #243049;
    --text: #e2e8f0;
    --text-soft: #94a3b8;
    --accent: #60a5fa;
    --accent-soft: #1e2a47;
    --danger: #f87171;

    --syn-comment: #7c8aa0;
    --syn-key: #7dd3fc;
    --syn-string: #86efac;
    --syn-keyword: #f0abfc;
    --syn-number: #fdba74;
  }
}

* { box-sizing: border-box; }

html { scroll-padding-top: calc(var(--topbar-h) + 16px); }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.65 var(--sans);
  -webkit-font-smoothing: antialiased;
}

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

/* ---------- top bar ---------- */
.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  height: var(--topbar-h);
  display: flex;
  align-items: center;
  gap: 24px;
  padding: 0 24px;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.brand {
  font-weight: 700;
  font-size: 18px;
  color: var(--text);
  letter-spacing: -0.01em;
}
.brand:hover { text-decoration: none; }
.brand-mark { color: var(--accent); }
.toplinks { margin-left: auto; display: flex; gap: 20px; font-size: 15px; }
.toplinks a { color: var(--text-soft); }
.toplinks a:hover { color: var(--text); text-decoration: none; }
.menu-toggle { display: none; }

/* ---------- layout ---------- */
.shell {
  display: flex;
  max-width: 1200px;
  margin: 0 auto;
}
.sidebar {
  position: sticky;
  top: var(--topbar-h);
  align-self: flex-start;
  width: var(--sidebar-w);
  flex-shrink: 0;
  height: calc(100vh - var(--topbar-h));
  padding: 28px 16px;
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
}
.sidebar nav { display: flex; flex-direction: column; gap: 2px; }
.sidebar nav a {
  padding: 7px 12px;
  border-radius: 8px;
  color: var(--text-soft);
  font-size: 15px;
}
.sidebar nav a:hover { background: var(--bg-soft); color: var(--text); text-decoration: none; }
.sidebar nav a.active { background: var(--accent-soft); color: var(--accent); font-weight: 600; }

.content {
  flex: 1;
  min-width: 0;
  max-width: 860px;
  padding: 40px 48px 64px;
}

/* ---------- typography ---------- */
.content h1 {
  font-size: 2.2rem;
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin: 0 0 20px;
}
.content h2 {
  font-size: 1.45rem;
  letter-spacing: -0.01em;
  margin: 48px 0 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}
.content h3 { font-size: 1.1rem; margin: 32px 0 8px; }
.content p, .content ul, .content ol { margin: 0 0 16px; }
.content li { margin: 4px 0; }
.content li > p { margin: 0; }
.content img {
  max-width: 100%;
  height: auto;
  border-radius: 10px;
  border: 1px solid var(--border);
  box-shadow: 0 8px 30px rgba(15, 23, 42, 0.15);
  margin: 8px 0 24px;
}
.content hr { border: 0; border-top: 1px solid var(--border); margin: 32px 0; }
.content blockquote {
  margin: 0 0 16px;
  padding: 8px 16px;
  border-left: 4px solid var(--accent);
  background: var(--bg-soft);
  border-radius: 0 8px 8px 0;
  color: var(--text-soft);
}

/* ---------- code ---------- */
code {
  font-family: var(--mono);
  font-size: 0.875em;
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.1em 0.4em;
}
pre {
  margin: 0 0 20px;
  padding: 16px 18px;
  overflow-x: auto;
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: 10px;
  line-height: 1.55;
}
pre code {
  background: none;
  border: 0;
  padding: 0;
  font-size: 13.5px;
}
div.highlighter-rouge { margin: 0 0 20px; }
div.highlighter-rouge pre { margin: 0; }

.highlight .c, .highlight .c1, .highlight .cm, .highlight .cs, .highlight .cp { color: var(--syn-comment); font-style: italic; }
.highlight .na, .highlight .nt, .highlight .nl, .highlight .py { color: var(--syn-key); }
.highlight .s, .highlight .s1, .highlight .s2, .highlight .sb, .highlight .sc,
.highlight .sd, .highlight .se, .highlight .sh, .highlight .si, .highlight .sx, .highlight .ss { color: var(--syn-string); }
.highlight .k, .highlight .kd, .highlight .kn, .highlight .kp, .highlight .kr, .highlight .kt, .highlight .kc, .highlight .nb { color: var(--syn-keyword); }
.highlight .m, .highlight .mi, .highlight .mf, .highlight .mh, .highlight .il, .highlight .no { color: var(--syn-number); }
.highlight .nf, .highlight .nc { color: var(--accent); }

/* ---------- tables ---------- */
.content table {
  display: block;
  width: 100%;
  overflow-x: auto;
  border-collapse: collapse;
  margin: 0 0 24px;
  font-size: 14.5px;
}
.content th, .content td {
  padding: 9px 12px;
  border: 1px solid var(--border);
  text-align: left;
  vertical-align: top;
}
.content th { background: var(--bg-soft); font-weight: 600; }
.content td code { white-space: nowrap; }
.content tr:nth-child(even) td { background: color-mix(in srgb, var(--bg-soft) 50%, transparent); }

/* ---------- footer ---------- */
.footer {
  margin-top: 64px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
  font-size: 14px;
  color: var(--text-soft);
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

/* ---------- mobile ---------- */
@media (max-width: 860px) {
  .topbar { padding: 0 16px; gap: 16px; }
  .toplinks { display: none; }
  .menu-toggle {
    display: block;
    margin-left: auto;
    padding: 6px 12px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 14px;
    cursor: pointer;
    color: var(--text);
  }
  .shell { display: block; }
  .sidebar {
    display: none;
    position: static;
    width: auto;
    height: auto;
    padding: 12px 16px;
    border-right: 0;
    border-bottom: 1px solid var(--border);
  }
  .menu-checkbox:checked ~ .shell .sidebar { display: block; }
  .content { padding: 28px 16px 48px; }
  .content h1 { font-size: 1.8rem; }
}