*, *::before, *::after { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--color-neutral-950);
  color: var(--text-secondary);
  font-family: var(--font-sans);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }

/* ── Nav ── */
.doc-nav {
  position: sticky; top: 0; z-index: 50;
  display: flex; align-items: center; justify-content: space-between;
  padding: 20px 56px;
  background: rgba(15,23,41,0.82);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--border-subtle);
}
.doc-nav-brand {
  font-weight: 800; font-size: 22px; letter-spacing: -.02em;
  color: var(--text-primary); text-decoration: none;
}
.doc-nav-back {
  display: inline-flex; align-items: center; gap: 6px;
  font-family: var(--font-mono); font-size: 11px; letter-spacing: 1.2px;
  text-transform: uppercase; color: var(--text-tertiary);
  text-decoration: none;
  transition: color .15s;
}
.doc-nav-back:hover { color: var(--color-brand-300); }
.doc-nav-back svg { transition: transform .2s; }
.doc-nav-back:hover svg { transform: translateX(-3px); }

/* ── Header ── */
.doc-header {
  padding: 80px 56px 32px;
  border-bottom: 1px solid var(--border-subtle);
  text-align: center;
  background:
    radial-gradient(ellipse 600px 300px at 50% 0%, rgba(80,149,231,0.07), transparent 70%),
    var(--color-neutral-950);
}
.doc-header-eyebrow {
  font-family: var(--font-mono); font-size: 10px; letter-spacing: 1.6px;
  text-transform: uppercase; color: var(--color-brand-300);
  margin: 0 0 20px;
}
.doc-header-title {
  font-size: clamp(32px, 4vw, 52px); font-weight: 700;
  letter-spacing: -.025em; line-height: 1.08;
  color: var(--text-primary); margin: 0 0 16px;
}
.doc-header-meta {
  font-family: var(--font-mono); font-size: 11px; letter-spacing: .6px;
  color: var(--text-muted);
}

/* ── Document body ── */
.doc-body {
  max-width: 800px;
  margin: 0 auto;
  padding: 36px 24px 120px;
}

.doc-section { margin-bottom: 56px; }

.doc-section-num {
  font-family: var(--font-mono); font-size: 10px; letter-spacing: 1.4px;
  text-transform: uppercase; color: var(--color-brand-300);
  margin: 0 0 10px;
}
.doc-section h2 {
  font-size: 20px; font-weight: 600; letter-spacing: -.01em;
  color: var(--text-primary);
  margin: 0 0 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border-subtle);
}
.doc-section p {
  font-size: 15px; line-height: 1.75;
  color: var(--text-tertiary);
  margin: 0 0 14px;
}
.doc-section ul, .doc-section ol {
  margin: 0 0 14px; padding-left: 20px;
}
.doc-section li {
  font-size: 15px; line-height: 1.75;
  color: var(--text-tertiary);
  margin-bottom: 6px;
}
.doc-section a {
  color: var(--color-brand-300);
  text-decoration: underline;
  text-underline-offset: 3px;
}
.doc-section a:hover { color: var(--color-brand-200); }
.doc-section strong { color: var(--text-secondary); font-weight: 600; }

.doc-subsection { margin-bottom: 24px; }
.doc-subsection-label {
  font-size: 12px; font-weight: 600; letter-spacing: .04em;
  text-transform: uppercase; color: var(--text-secondary);
  margin: 0 0 8px;
}

.doc-caps {
  font-size: 13px; line-height: 1.7;
  color: var(--text-tertiary);
  letter-spacing: .01em;
}

.doc-preamble {
  margin-bottom: 56px;
  padding: 24px;
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  background: rgba(255,255,255,0.02);
}
.doc-preamble p { margin: 0 0 10px; }
.doc-preamble p:last-child { margin: 0; }
.doc-preamble .doc-caps { font-weight: 500; color: var(--text-secondary); }

.doc-divider {
  border: none;
  border-top: 1px solid var(--border-subtle);
  margin: 56px 0;
}

/* ── Footer ── */
.doc-foot {
  background: var(--color-neutral-1000);
  border-top: 1px solid var(--border-subtle);
  padding: 32px 56px 28px;
}
.doc-foot-row {
  display: flex; align-items: center; justify-content: space-between;
  gap: 24px; flex-wrap: wrap;
}
.doc-foot-brand { font-weight: 800; font-size: 20px; letter-spacing: -.02em; color: var(--text-primary); }
.doc-foot-links { display: flex; gap: 28px; flex-wrap: wrap; }
.doc-foot-links a { color: var(--text-tertiary); font-size: 13px; transition: color .15s; }
.doc-foot-links a:hover { color: var(--text-primary); }
.doc-foot-copy {
  margin-top: 24px; padding-top: 18px;
  border-top: 1px solid var(--border-subtle);
  text-align: center;
  font-family: var(--font-mono); font-size: 10px; letter-spacing: 1.2px;
  text-transform: uppercase; color: var(--text-muted);
}

@media (max-width: 720px) {
  .doc-nav { padding: 16px 20px; }
  .doc-header { padding: 56px 20px 24px; }
  .doc-body { padding: 24px 20px 80px; }
  .doc-foot { padding: 24px 20px; }
  .doc-foot-row { flex-direction: column; align-items: flex-start; }
}