.site-header {
  position: sticky; top: 0; z-index: 100;
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border);
  height: 60px;
}
.site-header .container {
  height: 100%; display: flex; align-items: center; gap: var(--sp-8);
}
.site-logo {
  flex-shrink: 0;
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--fw-extrabold);
  color: var(--text-primary);
  letter-spacing: -0.02em;
}
.main-nav {
  display: flex; align-items: center; gap: var(--sp-1); flex: 1;
}
.nav-link {
  padding: var(--sp-2) var(--sp-3);
  border-radius: var(--r-sm);
  font-size: var(--text-sm);
  font-weight: var(--fw-medium);
  color: var(--text-secondary);
  transition: var(--transition);
  white-space: nowrap;
}
.nav-link:hover, .nav-link.active {
  color: var(--text-primary); background: var(--bg-elevated);
  text-decoration: none;
}
.header-search {
  margin-left: auto;
}
.menu-toggle {
  display: none;
  background: none; border: none; cursor: pointer;
  padding: var(--sp-2);
  flex-direction: column; gap: 5px;
}
.menu-toggle span {
  display: block; width: 22px; height: 2px;
  background: var(--text-primary);
  transition: var(--transition);
}
@media (max-width: 768px) {
  .menu-toggle { display: flex; margin-left: auto; }
  .main-nav {
    display: none; position: absolute; top: 60px; left: 0; right: 0;
    background: var(--bg-surface);
    border-bottom: 1px solid var(--border);
    flex-direction: column; padding: var(--sp-4);
    gap: var(--sp-1);
  }
  .main-nav.is-open { display: flex; }
  .nav-link { width: 100%; }
  .header-search { display: none; }
}