.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  height: var(--header-h);
  background: rgba(255, 255, 255, 0.82);
  -webkit-backdrop-filter: saturate(1.6) blur(14px);
          backdrop-filter: saturate(1.6) blur(14px);
}

.nav { height: 100%; display: flex; align-items: center; gap: 2.5rem; }

.logo {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  font-weight: 600;
  font-size: 1.2rem;
  letter-spacing: -0.03em;
  text-decoration: none;
}

.logo-mark {
  width: 28px;
  height: 28px;
  border-radius: 8px;
  background: var(--color-ink);
  display: grid;
  place-items: center;
}

.logo-mark path { fill: none; stroke: #fff; stroke-width: 2.4; stroke-linecap: round; }

.nav-links { display: flex; gap: 1.75rem; margin: 0; padding: 0; list-style: none; }

.nav-links a {
  text-decoration: none;
  color: var(--color-ink-soft);
  font-weight: 500;
  font-size: 0.95rem;
  transition: color var(--duration-fast) ease;
}

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

.nav-end { margin-left: auto; display: flex; align-items: center; gap: 0.75rem; }

.lang-switch {
  display: flex;
  gap: 2px;
  padding: 3px;
  border-radius: var(--radius-sm);
  background: var(--color-surface);
}

.lang-switch button {
  border: 0;
  background: transparent;
  cursor: pointer;
  padding: 0.35rem 0.55rem;
  border-radius: 7px;
  font: 500 0.78rem / 1 var(--font-mono);
  color: var(--color-muted);
  transition: background-color var(--duration-fast) ease, color var(--duration-fast) ease;
}

.lang-switch button:hover { color: var(--color-ink); }

.lang-switch button[aria-pressed="true"] {
  background: #fff;
  color: var(--color-ink);
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.08);
}

/* ---------- Mobile menu ---------- */
.menu-toggle {
  display: none;
  width: 40px;
  height: 40px;
  border: 0;
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  cursor: pointer;
  position: relative;
}

.menu-toggle span {
  position: absolute;
  left: 11px;
  right: 11px;
  height: 2px;
  border-radius: 2px;
  background: var(--color-ink);
  transition: transform 300ms var(--ease);
}

.menu-toggle span:first-child { transform: translateY(-4px); }
.menu-toggle span:last-child { transform: translateY(4px); }
.menu-toggle[aria-expanded="true"] span:first-child { transform: rotate(45deg); }
.menu-toggle[aria-expanded="true"] span:last-child { transform: rotate(-45deg); }

.mobile-menu {
  position: absolute;
  top: var(--header-h);
  left: 0;
  right: 0;
  padding: 0.5rem var(--gutter) 1.5rem;
  background: #fff;
  border-bottom: 1px solid var(--color-line);
  box-shadow: 0 24px 40px -24px rgba(0, 0, 0, 0.2);
  clip-path: inset(0 0 100% 0);
  visibility: hidden;
  transition: clip-path 450ms var(--ease), visibility 0s linear 450ms;
}

.mobile-menu.is-open {
  clip-path: inset(0 0 0 0);
  visibility: visible;
  transition: clip-path 450ms var(--ease), visibility 0s;
}

.mobile-menu ul { margin: 0 0 1.25rem; padding: 0; list-style: none; }

.mobile-menu li a {
  display: block;
  padding: 0.85rem 0;
  border-bottom: 1px solid var(--color-line);
  font-size: 1.5rem;
  font-weight: 500;
  letter-spacing: -0.03em;
  text-decoration: none;
}

.mobile-menu .btn { width: 100%; justify-content: center; padding: 0.9rem; }

@media (max-width: 760px) {
  .nav { gap: 1rem; }
  .lang-switch button { padding: 0.55rem 0.6rem; }
  .nav-links,
  .nav-end > .btn { display: none; }
  .menu-toggle { display: block; }
}

@media (min-width: 761px) {
  .mobile-menu { display: none; }
}