:root {
  --bg: #ffffff;
  --text: #111111;
  --muted: #555555;
  --border: #e7e7e7;
  --link: #0b57d0;

  --container: 760px;
  --radius: 10px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
  line-height: 1.6;
}

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 28px 18px 56px;
}

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

.header {
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border);
}

h1 {
  margin: 0;
  font-size: 34px;
  letter-spacing: -0.02em;
}

.subtitle {
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 16px;
}

.meta {
  margin: 12px 0 0;
  color: var(--muted);
  font-size: 14px;
}

.toc {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  padding: 14px 0 18px;
  margin: 0;
}

.toc a {
  display: inline-block;
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: #fafafa;
  font-size: 14px;
}

section {
  padding: 22px 0;
  border-top: 1px solid var(--border);
}

h2 {
  margin: 0 0 10px;
  font-size: 22px;
  letter-spacing: -0.01em;
}

h3 {
  margin: 18px 0 8px;
  font-size: 16px;
}

p {
  margin: 0 0 10px;
}

.lead {
  font-size: 17px;
}

ul {
  margin: 8px 0 10px 18px;
  padding: 0;
}

li { margin: 6px 0; }

.small {
  color: var(--muted);
  font-size: 14px;
}

.footer {
  margin-top: 22px;
  padding-top: 18px;
  border-top: 1px solid var(--border);
}

/* Small screens */
@media (max-width: 520px) {
  h1 { font-size: 28px; }
  .toc a { width: 100%; text-align: center; }
}