/* ─── Header & Navigation ────────────────────────────────────────────────── */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--header-h);
  display: flex;
  align-items: center;
  transition: all var(--transition-slow);
}
.site-header.scrolled {
  background: rgba(5,10,20,0.92);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--color-border);
  box-shadow: 0 4px 30px rgba(0,0,0,0.4);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  max-width: var(--content-wide);
  margin-inline: auto;
  padding-inline: clamp(var(--space-4), 4vw, var(--space-12));
}

/* Logo */
.site-logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  flex-shrink: 0;
}
.logo-mark {
  width: 36px;
  height: 36px;
  flex-shrink: 0;
}
.logo-text {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--color-text);
  letter-spacing: -0.02em;
}
.logo-text span {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* Main Nav */
.main-nav { display: flex; align-items: center; gap: var(--space-1); }
.nav-item { position: relative; }
.nav-link {
  display: flex;
  align-items: center;
  gap: 4px;
  padding: var(--space-2) var(--space-3);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-muted);
  border-radius: var(--radius-md);
  transition: all var(--transition);
  white-space: nowrap;
}
.nav-link:hover, .nav-link.active { color: var(--color-text); background: var(--color-surface-2); }
.nav-link svg { transition: transform var(--transition); flex-shrink: 0; }
.nav-item:hover .nav-link svg { transform: rotate(180deg); }

/* Mega Menu */
.mega-menu {
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%) translateY(-8px);
  width: 680px;
  background: rgba(8,15,31,0.97);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-2xl);
  padding: var(--space-6);
  box-shadow: var(--shadow-lg), 0 0 60px rgba(56,189,248,0.05);
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
  z-index: 2000;
}
.mega-menu.mega-menu--wide { width: 900px; }
.mega-menu.mega-menu--narrow { width: 280px; }
.nav-item:hover .mega-menu,
.nav-item:focus-within .mega-menu {
  opacity: 1;
  visibility: visible;
  pointer-events: all;
  transform: translateX(-50%) translateY(0);
}
.mega-menu-header {
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: var(--space-3);
  padding-bottom: var(--space-2);
  border-bottom: 1px solid var(--color-divider);
}
.mega-menu-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-2); }
.mega-menu-grid--2col { grid-template-columns: repeat(2, 1fr); }
.mega-menu-item {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  padding: var(--space-3);
  border-radius: var(--radius-lg);
  transition: all var(--transition);
  text-decoration: none;
  color: inherit;
}
.mega-menu-item:hover { background: var(--color-surface-2); }
.mega-menu-icon {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  background: var(--color-primary-bg);
  border: 1px solid var(--color-primary-border);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary);
  flex-shrink: 0;
  font-size: 16px;
}
.mega-menu-item-title {
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 2px;
}
.mega-menu-item-desc {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  line-height: 1.4;
}

/* Simple dropdown */
.dropdown-menu {
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 200px;
  background: rgba(8,15,31,0.97);
  backdrop-filter: blur(24px);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-2);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
  transform: translateY(-6px);
  z-index: 2000;
}
.nav-item:hover .dropdown-menu,
.nav-item:focus-within .dropdown-menu {
  opacity: 1; visibility: visible; pointer-events: all; transform: translateY(0);
}
.dropdown-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-2) var(--space-3);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  border-radius: var(--radius-md);
  transition: all var(--transition);
  text-decoration: none;
}
.dropdown-item:hover { background: var(--color-surface-2); color: var(--color-text); }

/* Header CTA */
.header-cta { display: flex; align-items: center; gap: var(--space-3); }
.lang-switcher {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  cursor: pointer;
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-md);
  transition: all var(--transition);
}
.lang-switcher:hover { color: var(--color-text); background: var(--color-surface-2); }

/* Mobile Nav */
.mobile-menu-btn {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: var(--space-2);
  cursor: pointer;
}
.mobile-menu-btn span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text);
  border-radius: var(--radius-full);
  transition: all var(--transition);
}
.mobile-menu-btn.active span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.mobile-menu-btn.active span:nth-child(2) { opacity: 0; transform: scaleX(0); }
.mobile-menu-btn.active span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.mobile-nav {
  position: fixed;
  top: var(--header-h);
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(5,10,20,0.98);
  backdrop-filter: blur(24px);
  z-index: 999;
  padding: var(--space-6);
  overflow-y: auto;
  transform: translateX(100%);
  transition: transform var(--transition-slow);
}
.mobile-nav.open { transform: translateX(0); }
.mobile-nav-group { margin-bottom: var(--space-6); }
.mobile-nav-group-title {
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: var(--space-3);
}
.mobile-nav-link {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-3) var(--space-4);
  font-size: var(--text-base);
  font-weight: 500;
  color: var(--color-text);
  border-radius: var(--radius-lg);
  transition: all var(--transition);
  text-decoration: none;
  margin-bottom: var(--space-1);
}
.mobile-nav-link:hover { background: var(--color-surface-2); color: var(--color-primary); }

@media (max-width: 1024px) {
  .main-nav { display: none; }
  .mobile-menu-btn { display: flex; }
  .header-cta .btn:not(.mobile-show) { display: none; }
}