.site-navbar {
  position: sticky;
  top: 0;
  z-index: 1200;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--gray-200);
}

.site-navbar-inner {
  min-height: 74px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand-logo {
  height: 36px;
  width: auto;
}

.desktop-nav {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.nav-group {
  position: relative;
}

.nav-group summary {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.45rem 0.75rem;
  border-radius: 8px;
  color: var(--gray-700, #334155);
  font-size: 0.95rem;
  font-weight: 500;
  cursor: pointer;
  list-style: none;
  transition: background-color 0.2s ease, color 0.2s ease;
}

.nav-group summary::-webkit-details-marker {
  display: none;
}

.nav-group summary:hover {
  background: var(--gray-100);
  color: var(--gray-900);
}

.nav-mega {
  position: absolute;
  top: calc(100% + 0.4rem);
  left: 0;
  width: 320px;
  max-height: 64vh;
  overflow: auto;
  background: #fff;
  border: 1px solid var(--gray-200);
  border-radius: 12px;
  box-shadow: 0 12px 24px rgba(15, 23, 42, 0.12);
  padding: 0.55rem;
  display: grid;
  gap: 0.2rem;
  z-index: 1400;
}

.nav-sub-link {
  display: block;
  min-height: 40px;
  border-radius: 8px;
  padding: 0.5rem 0.6rem;
  color: var(--gray-700);
  font-size: 0.92rem;
}

.nav-sub-link:hover,
.nav-sub-link.active {
  background: #eef2ff;
  color: var(--primary-strong);
}

.nav-start-btn {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.45rem 0.95rem;
  border-radius: 999px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #fff;
  font-weight: 600;
}

.nav-sub-link.active,
.mobile-nav-link.active {
  background: #eef2ff;
  color: var(--primary-strong);
}

.nav-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border: 1px solid var(--gray-200);
  background: #fff;
  border-radius: 10px;
  color: var(--gray-900);
  cursor: pointer;
}

.nav-toggle i {
  font-size: 1rem;
}

.nav-overlay {
  position: fixed;
  inset: 0;
  background: rgba(2, 6, 23, 0.45);
  opacity: 0;
  transition: opacity 0.24s ease;
}

.nav-overlay.open {
  opacity: 1;
}

.mobile-nav {
  position: fixed;
  top: 0;
  right: 0;
  height: 100vh;
  width: min(320px, 90vw);
  background: #fff;
  border-left: 1px solid var(--gray-200);
  box-shadow: -10px 0 30px rgba(15, 23, 42, 0.15);
  transform: translateX(100%);
  transition: transform 0.24s ease;
  z-index: 1300;
  padding: 6rem 1rem 1rem;
}

.mobile-nav.open {
  transform: translateX(0);
}

.mobile-nav-links {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.mobile-group {
  border: 1px solid var(--gray-200);
  border-radius: 10px;
  padding: 0.2rem 0.2rem 0.35rem;
  background: #fff;
}

.mobile-group summary {
  min-height: 44px;
  display: flex;
  align-items: center;
  padding: 0.45rem 0.7rem;
  list-style: none;
  cursor: pointer;
  color: var(--gray-900);
  font-weight: 600;
}

.mobile-group summary::-webkit-details-marker {
  display: none;
}

.mobile-nav-link {
  min-height: 44px;
  display: flex;
  align-items: center;
  padding: 0.7rem 0.9rem;
  border-radius: 8px;
  color: var(--gray-800);
  font-weight: 500;
}

@media (max-width: 1100px) {
  .desktop-nav {
    display: none;
  }

  .nav-toggle {
    display: inline-flex;
  }

  .brand-logo {
    height: 32px;
  }
}

@media (max-width: 768px) {
  .site-navbar-inner {
    min-height: 64px;
  }

  .mobile-nav {
    width: min(340px, 94vw);
    padding-top: 5.2rem;
  }
}