/* =====================================================
   ContactX · Header/Navigation Component
   ===================================================== */

/* ---------- 头部导航：毛玻璃固定 ---------- */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--nav-height);
  z-index: 1000;
  background: color-mix(in srgb, var(--bg) 78%, transparent);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--border);
  transition: box-shadow var(--transition-base);
}

.site-header.scrolled {
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.05);
}

.header-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 600;
  font-size: 17px;
  letter-spacing: -0.01em;
  color: var(--fg);
  transition: opacity var(--transition-fast);
}

.site-logo:hover {
  opacity: 0.8;
}

.site-logo .logo-mark {
  width: 26px; height: 26px;
  border-radius: 7px;
  background: var(--fg);
  color: var(--surface);
  display: grid;
  place-items: center;
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 600;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 4px;
  list-style: none;
}

.nav-link {
  font-size: 14px;
  font-weight: 450;
  color: var(--muted);
  padding: 7px 12px;
  border-radius: 7px;
  transition: color var(--transition-fast), background var(--transition-fast);
}

.nav-link:hover {
  color: var(--fg);
  background: var(--surface-2);
}

.nav-link.active {
  color: var(--fg);
}

.nav-item-cta {
  margin-left: 8px;
}

/* 移动端菜单按钮 */
.mobile-menu-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
  color: var(--fg);
}

.mobile-menu-toggle svg {
  width: 24px;
  height: 24px;
  display: block;
}

/* 响应式设计 */
@media (max-width: 720px) {
  .mobile-menu-toggle {
    display: block;
  }

  .site-nav {
    position: absolute;
    top: var(--nav-height);
    left: 0; right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    padding: 12px 16px 18px;
    transform: translateY(-8px);
    opacity: 0;
    visibility: hidden;
    transition: transform var(--transition-base), opacity var(--transition-base);
  }

  .site-nav.mobile-open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav-link {
    padding: 12px 10px;
  }

  .nav-item-cta {
    margin: 6px 0 0;
  }

  .nav-item-cta .btn-primary {
    width: 100%;
    justify-content: center;
  }
}