:root {
  --bg: #f2f2f0;
  --surface: rgba(255, 255, 255, 0.82);
  --surface-strong: #ffffff;
  --line: rgba(12, 12, 14, 0.08);
  --line-strong: rgba(12, 12, 14, 0.14);
  --text: #0d0d10;
  --muted: #616169;
  --accent: #151518;
  --accent-soft: rgba(12, 12, 14, 0.05);
  --shadow-lg: 0 26px 70px rgba(12, 12, 14, 0.10);
  --shadow-md: 0 14px 36px rgba(12, 12, 14, 0.07);
  --radius-2xl: 30px;
  --radius-xl: 22px;
  --max: 1180px;
  --header-h: 80px;
  color-scheme: light;
}

* { box-sizing: border-box; }
html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 18px);
}
body {
  margin: 0;
  font-family: Inter, "Inter Variable", ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background:
    radial-gradient(circle at 50% 0%, rgba(12, 12, 14, 0.05), transparent 28%),
    linear-gradient(180deg, #f7f7f5 0%, var(--bg) 44%, #ffffff 100%);
  color: var(--text);
}

a {
  color: inherit;
  text-decoration: none;
}

.container {
  width: min(var(--max), calc(100vw - 32px));
  margin: 0 auto;
}

.header {
  position: sticky;
  top: 0;
  z-index: 30;
  height: var(--header-h);
  background: rgba(248, 248, 246, 0.82);
  backdrop-filter: blur(18px);
  border-bottom: 1px solid rgba(8, 17, 31, 0.06);
}

.nav {
  min-height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  font-weight: 800;
  font-size: 17px;
  letter-spacing: -0.03em;
}

.brand-mark {
  position: relative;
  width: 38px;
  height: 38px;
  border-radius: 13px;
  background:
    radial-gradient(circle at 28% 22%, rgba(255, 255, 255, 0.92), transparent 24%),
    linear-gradient(145deg, #0f0f12 0%, #18181b 48%, #2a2a2f 100%);
  box-shadow: 0 16px 32px rgba(0, 0, 0, 0.18);
}

.brand-mark::before,
.brand-mark::after {
  content: "";
  position: absolute;
  border-radius: 10px;
  border: 1.4px solid rgba(255, 255, 255, 0.72);
}

.brand-mark::before { inset: 8px; }
.brand-mark::after {
  inset: 14px 11px 11px 14px;
  border-top-color: transparent;
  border-left-color: transparent;
}

.nav-links,
.header-actions {
  display: flex;
  align-items: center;
  gap: 18px;
}

.nav-links a {
  font-size: 14px;
  font-weight: 600;
  color: var(--muted);
}

.nav-links a:hover {
  color: var(--text);
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 0 18px;
  border-radius: 15px;
  background: linear-gradient(145deg, #050506 0%, #121214 40%, var(--accent) 100%);
  color: #fff;
  font-size: 14px;
  font-weight: 700;
  box-shadow: 0 18px 34px rgba(12, 12, 14, 0.12);
}

.hero {
  padding: 42px 0 30px;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-height: 42px;
  padding: 0 15px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.78);
  border: 1px solid rgba(12, 12, 14, 0.10);
  box-shadow: 0 10px 24px rgba(8, 17, 31, 0.04);
  color: #2a2a30;
  font-size: 13px;
  font-weight: 700;
}

.eyebrow::before {
  content: "";
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: linear-gradient(180deg, #f4f4f5 0%, #cfcfd4 100%);
  box-shadow: 0 0 0 5px rgba(255, 255, 255, 0.08);
}

.hero h1 {
  margin: 18px 0 0;
  font-size: clamp(42px, 7vw, 76px);
  line-height: 0.94;
  letter-spacing: -0.06em;
  max-width: 900px;
}

.hero p {
  max-width: 920px;
  margin: 18px 0 0;
  font-size: 17px;
  line-height: 1.78;
  color: var(--muted);
}

.layout {
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  gap: 22px;
  padding-bottom: 50px;
}

.toc,
.content-card,
.section-card,
.footer-card {
  border: 1px solid var(--line);
  background: var(--surface);
  backdrop-filter: blur(12px);
  box-shadow: var(--shadow-md);
}

.toc {
  position: sticky;
  top: calc(var(--header-h) + 18px);
  align-self: start;
  border-radius: var(--radius-xl);
  padding: 20px;
}

.toc h2 {
  margin: 0 0 14px;
  font-size: 14px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

.toc ol,
.toc nav {
  margin: 0;
  padding-left: 18px;
  display: grid;
  gap: 12px;
}

.toc a {
  color: inherit;
  font-weight: 600;
}

.toc a:hover { color: var(--text); }

.content-card {
  border-radius: var(--radius-2xl);
  padding: 22px;
}

.section-card {
  border-radius: 24px;
  padding: 24px;
  background: var(--surface-strong);
}

.section-card + .section-card {
  margin-top: 18px;
}

.section-card[id] {
  scroll-margin-top: calc(var(--header-h) + 16px);
}

.section-card h2 {
  margin: 0 0 16px;
  font-size: clamp(28px, 4vw, 42px);
  line-height: 1.04;
  letter-spacing: -0.05em;
}

.section-card p,
.section-card li {
  color: #4f4f56;
  font-size: 16px;
  line-height: 1.78;
}

.section-card p {
  margin: 0 0 14px;
}

.section-card p:last-child {
  margin-bottom: 0;
}

.section-card ol,
.section-card ul {
  margin: 0;
  padding-left: 22px;
  display: grid;
  gap: 10px;
}

.muted-note {
  color: var(--muted);
}

.footer {
  padding: 0 0 34px;
}

.footer-card {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  border-radius: 22px;
  padding: 18px 20px;
  color: var(--muted);
  font-size: 14px;
}

@media (max-width: 980px) {
  .layout {
    grid-template-columns: 1fr;
  }

  .toc {
    position: static;
  }
}

@media (max-width: 760px) {
  .container {
    width: min(var(--max), calc(100vw - 20px));
  }

  .header {
    position: static;
  }

  .nav-links {
    display: none;
  }

  .hero {
    padding-top: 30px;
  }

  .content-card,
  .section-card {
    padding: 18px;
  }

  .footer-card {
    flex-direction: column;
    align-items: flex-start;
  }
}


.links {
  display: flex;
  align-items: center;
  gap: 18px;
}

.links a {
  font-size: 14px;
  font-weight: 600;
  color: var(--muted);
}

.links a:hover {
  color: var(--text);
}

.buttons {
  display: flex;
  align-items: center;
  gap: 12px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 46px;
  padding: 0 18px;
  border-radius: 15px;
  border: 1px solid transparent;
  font-size: 14px;
  font-weight: 700;
}

.btn-primary {
  background: linear-gradient(145deg, #050506 0%, #121214 40%, var(--accent) 100%);
  color: #fff;
  box-shadow: 0 18px 34px rgba(12, 12, 14, 0.12);
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-height: 42px;
  padding: 0 15px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.78);
  border: 1px solid rgba(12, 12, 14, 0.10);
  box-shadow: 0 10px 24px rgba(8, 17, 31, 0.04);
  color: #2a2a30;
  font-size: 13px;
  font-weight: 700;
}

.badge::before {
  content: "";
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: linear-gradient(180deg, #f4f4f5 0%, #cfcfd4 100%);
  box-shadow: 0 0 0 5px rgba(255, 255, 255, 0.08);
}

.panel {
  border: 1px solid var(--line);
  background: var(--surface);
  backdrop-filter: blur(12px);
  box-shadow: var(--shadow-md);
}

.content {
  border-radius: var(--radius-2xl);
  padding: 22px;
}

.section {
  border-radius: 24px;
  padding: 24px;
  background: var(--surface-strong);
  border: 1px solid var(--line);
}

.section + .section {
  margin-top: 18px;
}

.section h2 {
  margin: 0 0 16px;
  font-size: clamp(28px, 4vw, 42px);
  line-height: 1.04;
  letter-spacing: -0.05em;
}

.section p,
.section li {
  color: #4f4f56;
  font-size: 16px;
  line-height: 1.78;
}

.section ol,
.section ul {
  margin: 0;
  padding-left: 22px;
  display: grid;
  gap: 10px;
}

.back-row {
  margin-top: 18px;
}

.back-link {
  display: inline-flex;
  align-items: center;
  min-height: 42px;
  padding: 0 14px;
  border-radius: 999px;
  background: var(--accent-soft);
  color: #2a2a30;
  font-size: 14px;
  font-weight: 700;
}

.back-link:hover {
  color: var(--text);
}