* { box-sizing: border-box; }
:root {
  --bg: #f7f9fc;
  --paper: #ffffff;
  --ink: #111827;
  --muted: #5f6b7a;
  --line: #dfe6ef;
  --brand: #2855e5;
  --brand-dark: #1f43b8;
  --soft: #eef3ff;
  --ok: #15803d;
  --warn: #a16207;
  --maxw: 960px;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b1220;
    --paper: #111a2d;
    --ink: #edf2fb;
    --muted: #aab6c9;
    --line: #253553;
    --brand: #5d82ff;
    --brand-dark: #8ba6ff;
    --soft: #18243d;
  }
}
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Inter, Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; }
.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  background: color-mix(in srgb, var(--paper) 92%, transparent);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line);
}
.topbar-inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  font-weight: 850;
  letter-spacing: -0.02em;
}
.brand img {
  width: 34px;
  height: 34px;
  border-radius: 10px;
}
.nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 8px;
}
.nav a {
  color: var(--muted);
  border: 1px solid transparent;
  border-radius: 999px;
  padding: 7px 11px;
  text-decoration: none;
  font-size: 14px;
  font-weight: 750;
}
.nav a[aria-current="page"] {
  color: var(--brand-dark);
  background: var(--soft);
  border-color: color-mix(in srgb, var(--brand) 22%, transparent);
}
.wrap {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 34px 20px 56px;
}
.hero {
  padding: 30px 0 22px;
  border-bottom: 1px solid var(--line);
}
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--soft);
  color: var(--brand-dark);
  border-radius: 999px;
  padding: 6px 11px;
  font-size: 12px;
  font-weight: 850;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
h1 {
  margin: 16px 0 10px;
  font-size: clamp(32px, 6vw, 54px);
  line-height: 1.05;
  letter-spacing: -0.035em;
}
.lead {
  max-width: 720px;
  color: var(--muted);
  font-size: clamp(17px, 2vw, 20px);
}
.meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 20px;
  color: var(--muted);
  font-size: 14px;
}
.meta span {
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 6px 10px;
  background: var(--paper);
}
.layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 250px;
  gap: 28px;
  align-items: start;
  padding-top: 28px;
}
article {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: clamp(22px, 4vw, 38px);
}
.toc {
  position: sticky;
  top: 86px;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 16px;
}
.toc strong {
  display: block;
  font-size: 13px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 10px;
}
.toc a {
  display: block;
  color: var(--muted);
  text-decoration: none;
  padding: 7px 0;
  font-weight: 700;
  font-size: 14px;
}
.toc a:hover { color: var(--brand-dark); }
h2 {
  margin: 32px 0 10px;
  font-size: clamp(22px, 3vw, 30px);
  line-height: 1.2;
  letter-spacing: -0.02em;
}
h2:first-child { margin-top: 0; }
h3 {
  margin: 24px 0 8px;
  font-size: 18px;
  line-height: 1.3;
}
p { margin: 0 0 14px; }
ul {
  margin: 0 0 18px;
  padding-left: 22px;
}
li { margin: 7px 0; }
.note {
  margin: 22px 0;
  border-left: 4px solid var(--brand);
  background: var(--soft);
  border-radius: 10px;
  padding: 14px 16px;
}
.warning {
  border-left-color: var(--warn);
}
.ok {
  color: var(--ok);
  font-weight: 800;
}
.contact {
  margin-top: 30px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  color: var(--muted);
}
.contact a { color: var(--brand-dark); font-weight: 800; }
.footer {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 20px 34px;
  color: var(--muted);
  font-size: 14px;
}
@media (max-width: 780px) {
  .topbar-inner { align-items: flex-start; flex-direction: column; }
  .nav { justify-content: flex-start; }
  .wrap { padding-top: 22px; }
  .layout { grid-template-columns: 1fr; }
  .toc { position: static; order: -1; }
}