:root {
  --brand-blue: #0496FF;
  --brand-indigo: #300A6E;
  --brand-crimson: #FB5012;
  --brand-platinum: #EBEBEB;
  --ink: #1a1a2e;
  --muted: #5a5a72;
  --bg: #ffffff;
  --code-bg: #f5f5fa;
  --border: #e2e2ec;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.65;
  color: var(--ink);
  background: var(--bg);
  margin: 0;
}
.wrap {
  max-width: 880px;
  margin: 0 auto;
  padding: 40px 28px 120px;
}
h1, h2, h3, h4 {
  color: var(--brand-indigo);
  line-height: 1.25;
  letter-spacing: -0.01em;
}
h1 {
  font-size: 2rem;
  border-bottom: 4px solid var(--brand-blue);
  padding-bottom: 14px;
  margin-top: 0.2em;
}
h2 {
  font-size: 1.5rem;
  border-bottom: 2px solid var(--brand-platinum);
  padding-bottom: 8px;
  margin-top: 2.2em;
  scroll-margin-top: 20px;
}
h3 { font-size: 1.18rem; margin-top: 1.8em; }
a { color: var(--brand-blue); text-decoration: none; }
a:hover { text-decoration: underline; }
p { margin: 0.7em 0; }
strong { color: var(--brand-indigo); }
hr {
  border: none;
  border-top: 3px solid var(--brand-crimson);
  margin: 2.6em 0;
  width: 80px;
}
blockquote {
  margin: 1em 0;
  padding: 2px 18px;
  border-left: 4px solid var(--brand-blue);
  background: var(--brand-platinum);
  color: var(--muted);
}
table {
  border-collapse: collapse;
  width: 100%;
  margin: 1.2em 0;
  font-size: 0.93rem;
}
th, td {
  border: 1px solid var(--border);
  padding: 8px 10px;
  text-align: left;
  vertical-align: top;
}
th { background: var(--brand-indigo); color: #fff; font-weight: 600; }
tr:nth-child(even) td { background: #fafafe; }
code {
  background: var(--code-bg);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.88em;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
}
ul, ol { padding-left: 1.4em; }
li { margin: 0.35em 0; }
/* TOC */
nav#TOC {
  background: var(--brand-platinum);
  border-radius: 8px;
  padding: 14px 22px;
  margin: 22px 0 34px;
  font-size: 0.95rem;
}
nav#TOC > ul { list-style: none; padding-left: 0; margin: 0; }
nav#TOC > ul > li { margin: 6px 0; }
nav#TOC ul ul { list-style: none; margin: 4px 0 4px 0; padding-left: 1.2em; }
nav#TOC a { color: var(--brand-indigo); font-weight: 500; }
nav#TOC a:hover { color: var(--brand-crimson); }
.meta-line {
  color: var(--muted);
  font-size: 0.95rem;
  margin-bottom: 8px;
}