/* ============================================================
   Header & Navigation Styles (Synced with Homepage zh/index.html)
   ============================================================ */

.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  height: var(--header-h);
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(0, 74, 173, 0.10);
  transition: all 0.3s ease;
}
.site-header.scrolled {
  box-shadow: 0 4px 24px rgba(0, 74, 173, 0.12);
}
.header-inner {
  max-width: 1440px;
  margin: 0 auto;
  padding: 0 3.5rem;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
}

/* ── Logo ── */
.site-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-shrink: 0;
  text-decoration: none;
}
.site-logo img {
  height: 46px;
  width: auto;
}

/* ── Navigation ── */
.site-nav {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.nav-item {
  position: relative;
}
.nav-link {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  padding: 0.6rem 1.1rem;
  font-size: 1.125rem;
  font-weight: 500;
  color: var(--navy);
  border-radius: 8px;
  transition: all 0.25s ease;
  white-space: normal;
  word-break: keep-all;
}
.nav-link:hover, .nav-link.active {
  color: var(--cyan);
  background: rgba(47, 232, 250, 0.12);
}
.nav-link .chevron, .nav-link .chev { 
  font-size: 0.65rem; 
  opacity: 0.7; 
  transition: transform 0.25s; 
}
.nav-item:hover > .nav-link .chevron, 
.nav-item:hover > .nav-link .chev { transform: rotate(180deg); }

/* ── Dropdown ── */
.dropdown {
  position: absolute;
  top: calc(100% + 6px);
  left: 0;
  min-width: 200px;
  background: #fff;
  border: 1px solid rgba(0,74,173,0.1);
  border-radius: 14px;
  box-shadow: 0 12px 40px rgba(0,74,173,0.12);
  padding: 0.5rem;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-8px);
  transition: opacity 0.25s, transform 0.25s, visibility 0.25s;
  z-index: 200;
}
.nav-item:hover > .dropdown,
.nav-item:focus-within > .dropdown {
  opacity: 1; visibility: visible; transform: translateY(0);
}
.dropdown-item {
  display: block;
  padding: 0.6rem 0.9rem;
  font-size: 0.85rem;
  color: #1a1a2e;
  border-radius: 9px;
  transition: all 0.2s;
}
.dropdown-item:hover { 
  background: rgba(47,232,250,0.12); 
  color: var(--navy); 
  padding-left: 1.1rem; 
}
.dropdown-divider, .dropdown-sep {
  height: 1px;
  background: rgba(0,74,173,0.08);
  margin: 0.3rem 0.5rem;
}
.dropdown-cat {
  display: block;
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: #8899bb;
  padding: 0.5rem 0.9rem 0.25rem;
}

/* ── Mega Dropdown ── */
.dropdown-mega {
  min-width: 480px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.5rem 1.5rem;
  padding: 1rem;
}
.dropdown-col-title {
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: #8899bb;
  padding: 0 0.5rem 0.4rem;
  border-bottom: 1px solid rgba(0,74,173,0.08);
  margin-bottom: 0.25rem;
  display: block;
}

/* ── Header Right ── */
.header-right { 
  display: flex; 
  align-items: center; 
  gap: 0.75rem; 
  flex-shrink: 0; 
}
.lang-btn {
  display: flex; align-items: center; gap: 0.35rem;
  padding: 0.4rem 0.9rem;
  background: var(--navy);
  color: #fff;
  border-radius: 100px;
  font-size: 0.78rem;
  font-weight: 600;
  transition: 0.25s;
  cursor: pointer;
}
.lang-btn:hover { 
  background: var(--cyan); 
  color: var(--navy); 
  transform: scale(1.05);
  box-shadow: 0 4px 16px rgba(47,232,250,0.35);
}
.lang-switcher .dropdown .dropdown-item.active {
  color: var(--navy);
  font-weight: 700;
  background: rgba(47,232,250,0.12);
}

/* Contact Button style (if used) */
.contact-btn {
  padding: 0.55rem 1.2rem;
  background: var(--cyan);
  color: var(--navy);
  font-size: 0.85rem;
  font-weight: 700;
  border-radius: 10px;
  transition: 0.25s;
}
.contact-btn:hover {
  background: #00d0e6;
  box-shadow: 0 4px 16px rgba(47,232,250,0.4);
  transform: translateY(-2px);
}

/* ── Mobile Menu Toggle ── */
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  width: 40px; height: 40px;
  align-items: center; justify-content: center;
  background: transparent;
  border: 1.5px solid rgba(0,74,173,0.15);
  border-radius: 10px;
  cursor: pointer;
  transition: 0.25s;
}
.menu-toggle:hover { border-color: var(--cyan); }
.menu-toggle span {
  display: block; width: 20px; height: 2px;
  background: var(--navy); border-radius: 1px;
  transition: 0.3s;
}
.menu-toggle.open span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.menu-toggle.open span:nth-child(2) { opacity: 0; }
.menu-toggle.open span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

/* ── Mobile Nav ── */
.mobile-nav {
  display: none;
  position: fixed;
  top: var(--header-h); left: 0; right: 0;
  background: #fff;
  border-bottom: 1px solid rgba(0,74,173,0.08);
  box-shadow: 0 8px 32px rgba(0,74,173,0.1);
  z-index: 999;
  padding: 1rem;
  max-height: calc(100vh - var(--header-h));
  overflow-y: auto;
}
.mobile-nav.open { display: block; }
.mobile-nav-item { margin-bottom: 0.25rem; }
.mobile-nav-link {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.8rem 1rem;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--navy);
  border-radius: 10px;
  transition: 0.2s;
  width: 100%;
}
.mobile-nav-link:hover { background: rgba(47,232,250,0.12); }
.mobile-sub { padding-left: 1rem; display: none; }
.mobile-sub.open { display: block; }
.mobile-sub-item {
  display: block;
  padding: 0.5rem 0.75rem;
  font-size: 0.83rem;
  color: #556;
  border-radius: 8px;
  transition: 0.2s;
}
.mobile-sub-item:hover { color: var(--navy); background: rgba(47,232,250,0.1); }
.mobile-sub-cat {
  display: block;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: #8899bb;
  padding: 0.65rem 0.75rem 0.25rem;
}

@media (max-width: 1023px) {
  .site-nav { display: none; }
  .header-right { display: flex; } /* Keep lang btn on mobile? */
  .menu-toggle { display: flex; }
  .header-inner { padding: 0 1.5rem; }
}

@media (max-width: 767px) {
  .header-inner { padding: 0 1.25rem; }
}