.site-header {
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.site-header .container {
  align-items: center;
  display: flex;
  gap: 20px;
  min-height: 64px;
}

.brand {
  align-items: center;
  color: var(--text);
  display: flex;
  font-size: 1.0625rem;
  font-weight: 600;
  gap: 10px;
  letter-spacing: -0.01em;
  text-decoration: none;
}
.brand .mark { height: 26px; }

.site-nav { align-items: center; display: flex; gap: 22px; margin-left: auto; }
.site-nav a { font-size: 0.9375rem; font-weight: 500; }

@media (max-width: 640px) { .site-nav .nav-secondary { display: none; } }

.theme-btn {
  align-items: center;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--muted);
  cursor: pointer;
  display: inline-flex;
  height: 36px;
  justify-content: center;
  transition: border-color .14s ease, color .14s ease;
  width: 36px;
}
.theme-btn:hover { border-color: color-mix(in srgb, var(--accent) 45%, var(--border)); color: var(--text); }

.theme-icon { display: none; }
:root:not([data-theme]) .theme-icon--auto,
:root[data-theme="light"] .theme-icon--light,
:root[data-theme="dark"] .theme-icon--dark { display: block; }

.hero { padding-block: clamp(56px, 9vw, 104px); max-width: 900px; }
.hero .mark { margin-bottom: 28px; }
.hero h1 { margin-bottom: 20px; }
.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 32px;
}

.section-head { margin-bottom: 40px; max-width: 62ch; }
.section-head h2 { margin-bottom: 12px; }

.step-num {
  color: var(--muted);
  display: block;
  font-size: 0.8125rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  margin-bottom: 10px;
}

.site-footer {
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.875rem;
  padding-block: 40px;
}
.site-footer .container {
  align-items: center;
  display: flex;
  flex-wrap: wrap;
  gap: 16px 24px;
}
.site-footer .mark { height: 22px; }
.footer-spacer { flex: 1; }
.footer-links { display: flex; flex-wrap: wrap; gap: 18px; }

@media (max-width: 560px) {
  .site-footer .container { justify-content: center; text-align: center; }
  .footer-spacer { display: none; }
}