.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  padding: 14px 0;
  transition: all var(--transition-base);
}

.site-header.scrolled {
  background: rgba(10, 14, 26, 0.95);
  backdrop-filter: blur(16px);
  padding: 8px 0;
  border-bottom: 1px solid var(--color-border);
}

.header-inner {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: var(--container-padding);
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.logo-img {
  height: 44px;
  width: auto;
  display: block;
}
.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-display);
  font-size: 1.4rem;
  font-weight: 800;
  letter-spacing: -0.01em;
}

.logo-icon {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.65rem;
  font-weight: 700;
  color: var(--color-bg-dark);
  letter-spacing: 0;
}

.logo-text-legacy { color: var(--color-text-bright); }
.logo-text-iot { color: var(--color-primary); }
.logo-tagline {
  font-size: 0.55rem;
  font-weight: 400;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  display: block;
  margin-top: -2px;
}

.main-nav { flex: 1; display: flex; justify-content: center; }

.nav-list {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-item > a {
  display: flex;
  align-items: center;
  gap: 5px;
  padding: 8px 14px;
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--color-text-muted);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.nav-item > a:hover {
  color: var(--color-primary);
  background: rgba(0,200,255,0.06);
}

.nav-item.has-dropdown { position: relative; }

.dropdown {
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 260px;
  background: var(--color-bg-dark-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-card);
  padding: 10px;
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: all var(--transition-base);
}

.nav-item.has-dropdown:hover .dropdown {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.dropdown a {
  display: block;
  padding: 10px 14px;
  font-size: 0.88rem;
  color: var(--color-text-muted);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.dropdown a:hover {
  background: rgba(0,200,255,0.08);
  color: var(--color-primary);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.header-actions .btn-primary {
  padding: 9px 22px;
  font-size: 0.85rem;
}

.btn-login {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--color-text-muted);
  padding: 8px 12px;
}

.btn-login:hover { color: var(--color-primary); }

/* Mobile toggle */
.mobile-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
  z-index: 1001;
}

.mobile-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text-bright);
  border-radius: 2px;
  transition: all var(--transition-base);
}

.mobile-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}
.mobile-toggle.active span:nth-child(2) { opacity: 0; }
.mobile-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}