:root {
  --bg: #ffffff;
  --surface: #f6f7f8;
  --text: #0b0d10;
  --muted: #5b626b;
  --line: #e4e6e9;
  --accent: #1f5eff;
  --mark: #fff3bf;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b0d10;
    --surface: #13161a;
    --text: #eef0f2;
    --muted: #949ba4;
    --line: #23272d;
    --accent: #6b93ff;
    --mark: #4a3f10;
  }
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 400 16px/1.7 Inter, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); }
.wrap { max-width: 760px; margin: 0 auto; padding: 0 24px; }

/* Header */
header { border-bottom: 1px solid var(--line); }
header .wrap { display: flex; align-items: center; justify-content: space-between; height: 64px; max-width: 1080px; }
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--text); font-weight: 600; letter-spacing: .08em; font-size: 15px; }
.brand svg { width: 26px; height: 26px; }
header nav { display: flex; gap: 24px; font-size: 15px; }
header nav a { text-decoration: none; color: var(--muted); }
header nav a:hover, header nav a[aria-current="page"] { color: var(--text); }

/* Document */
main { padding: 72px 0 96px; }
.eyebrow { font-size: 13px; font-weight: 500; letter-spacing: .14em; text-transform: uppercase; color: var(--muted); margin: 0 0 16px; }
h1 { font-size: clamp(32px, 5vw, 44px); line-height: 1.1; letter-spacing: -0.025em; font-weight: 600; margin: 0 0 12px; }
.meta { color: var(--muted); font-size: 15px; margin: 0 0 40px; }
.summary { background: var(--surface); border: 1px solid var(--line); border-radius: 10px; padding: 20px 24px; margin: 0 0 40px; }
.summary p { margin: 0; }
.toc { border-left: 2px solid var(--line); padding-left: 20px; margin: 0 0 56px; }
.toc p { margin: 0 0 8px; font-size: 13px; font-weight: 500; letter-spacing: .1em; text-transform: uppercase; color: var(--muted); }
.toc ol { margin: 0; padding-left: 20px; font-size: 15px; columns: 2; column-gap: 32px; }
.toc a { color: var(--text); text-decoration: none; }
.toc a:hover { color: var(--accent); }
h2 { font-size: 21px; font-weight: 600; letter-spacing: -0.01em; margin: 48px 0 12px; scroll-margin-top: 24px; }
h3 { font-size: 17px; font-weight: 600; margin: 28px 0 8px; }
p, li { color: var(--text); }
ul { padding-left: 22px; }
li { margin-bottom: 6px; }
.caps { text-transform: uppercase; font-size: 14.5px; }
mark.todo { background: var(--mark); color: inherit; padding: 0 4px; border-radius: 3px; }

/* Support */
.contact-card { display: flex; align-items: center; justify-content: space-between; gap: 24px; flex-wrap: wrap; background: var(--surface); border: 1px solid var(--line); border-radius: 12px; padding: 28px; margin: 0 0 8px; }
.contact-card h2 { margin: 0 0 4px; }
.contact-card p { margin: 0; color: var(--muted); }
.btn { display: inline-block; padding: 12px 22px; border-radius: 8px; background: var(--text); color: var(--bg); text-decoration: none; font-weight: 500; }
.btn:hover { opacity: .85; }

/* Index cards */
.links { display: grid; gap: 1px; background: var(--line); border: 1px solid var(--line); border-radius: 12px; overflow: hidden; margin-top: 40px; }
.links a { display: block; background: var(--bg); padding: 28px 28px; text-decoration: none; color: var(--text); }
.links a:hover { background: var(--surface); }
.links strong { display: block; font-size: 18px; font-weight: 600; margin-bottom: 4px; }
.links span { color: var(--muted); font-size: 15px; }

footer { border-top: 1px solid var(--line); padding: 28px 0; font-size: 14px; color: var(--muted); }
footer .wrap { display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; max-width: 1080px; }
footer a { color: var(--muted); }

@media (max-width: 640px) {
  header .wrap { padding: 0 16px; gap: 16px; }
  .brand { white-space: nowrap; font-size: 13px; letter-spacing: .04em; gap: 8px; }
  .brand svg { width: 22px; height: 22px; }
  header nav { gap: 12px; font-size: 14px; }
  main { padding: 48px 0 72px; }
  .toc ol { columns: 1; }
}