.site-header {
  position: sticky;
  top: 0;
  z-index: 80;
  height: var(--nav-h);
  border-bottom: 1px solid transparent;
  background: transparent;
  transition: background var(--t-med) var(--ease), border-color var(--t-med) var(--ease), backdrop-filter var(--t-med) var(--ease);
}

.site-header.is-scrolled {
  background: var(--nav-bg);
  border-bottom-color: var(--border);
  backdrop-filter: blur(18px);
}

.nav-bar {
  height: var(--nav-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}

.logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  letter-spacing: -0.04em;
}

.logo-mark {
  width: 32px;
  height: 32px;
  display: grid;
  place-items: center;
  border-radius: 9px;
  background: var(--text-primary);
  color: var(--background);
  font-family: var(--font-mono);
  font-size: 12px;
}

.logo-text {
  display: flex;
  flex-direction: column;
  line-height: 1.05;
}

.logo-text small {
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-links a {
  position: relative;
  padding: 8px 12px;
  color: var(--text-secondary);
  font-size: 0.95rem;
  font-weight: 500;
  border-radius: var(--radius-full);
  transition: color var(--t-fast) var(--ease);
}

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

.nav-links a[aria-current="page"]::after,
.nav-links a.is-active::after {
  content: "";
  position: absolute;
  left: 12px;
  right: 12px;
  bottom: 4px;
  height: 1px;
  background: var(--accent);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.icon-btn {
  width: 42px;
  height: 42px;
  display: grid;
  place-items: center;
  border: 1px solid var(--border);
  border-radius: var(--radius-full);
  background: var(--surface);
  color: var(--text-primary);
  transition: transform var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease), background var(--t-fast) var(--ease);
}

.icon-btn:hover {
  border-color: var(--border-strong);
  transform: translateY(-1px);
}

.icon-btn svg {
  width: 18px;
  height: 18px;
}

.menu-toggle {
  display: none;
}

.mobile-drawer {
  display: none;
}

.site-footer {
  border-top: 1px solid var(--border);
  padding: var(--space-8) 0 var(--space-6);
  background: var(--surface);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr;
  gap: var(--space-7);
}

.footer-brand p {
  margin-top: var(--space-4);
  max-width: 28ch;
  color: var(--text-secondary);
}

.footer-col h3 {
  margin-bottom: var(--space-4);
  font-size: 0.78rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.footer-col a,
.footer-col button.linkish {
  display: block;
  margin-bottom: 10px;
  color: var(--text-secondary);
  text-align: left;
}

.footer-col a:hover,
.footer-col button.linkish:hover {
  color: var(--text-primary);
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  gap: var(--space-4);
  flex-wrap: wrap;
  margin-top: var(--space-8);
  padding-top: var(--space-5);
  border-top: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.9rem;
}

@media (max-width: 960px) {
  .nav-links,
  .btn.nav-cta {
    display: none;
  }

  .menu-toggle {
    display: grid;
  }

  .mobile-drawer {
    display: block;
    position: fixed;
    inset: 0;
    z-index: 90;
    pointer-events: none;
  }

  .mobile-drawer.is-open {
    pointer-events: auto;
  }

  .drawer-backdrop {
    position: absolute;
    inset: 0;
    background: var(--overlay);
    opacity: 0;
    transition: opacity var(--t-med) var(--ease);
  }

  .mobile-drawer.is-open .drawer-backdrop {
    opacity: 1;
  }

  .drawer-panel {
    position: absolute;
    top: 0;
    right: 0;
    width: min(100%, 360px);
    height: 100%;
    padding: 88px var(--space-6) var(--space-6);
    background: var(--surface);
    transform: translateX(100%);
    transition: transform var(--t-slow) var(--ease-out);
    overflow: auto;
  }

  .mobile-drawer.is-open .drawer-panel {
    transform: none;
  }

  .drawer-panel a {
    display: block;
    padding: 14px 0;
    border-bottom: 1px solid var(--border);
    font-size: 1.2rem;
    font-weight: 600;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 640px) {
  .container,
  .container-wide {
    width: min(calc(100% - 28px), var(--container));
  }

  .section {
    padding: var(--space-8) 0;
  }

  .footer-grid {
    grid-template-columns: 1fr;
  }
}