body {
  font-family: 'Inter', sans-serif;
  background: linear-gradient(to bottom, #f9fafb, #f3f4f6);
  color: #374151;
}

.gradient-bg {
  background: linear-gradient(120deg, #6366f1, #8b5cf6);
}

.logo-img {
  width: 88px;
  height: 104px;
  object-fit: contain;
}

.page-card {
  background: rgba(255, 255, 255, 0.96);
  border: 1px solid rgba(99, 102, 241, 0.08);
  box-shadow: 0 20px 45px -25px rgba(99, 102, 241, 0.25);
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.08fr) minmax(280px, 0.92fr);
  gap: 28px;
  align-items: center;
}

.hero-illustration {
  position: relative;
  min-height: 280px;
  overflow: hidden;
}

.hero-illustration::before {
  content: "";
  position: absolute;
  inset: 18px;
  border-radius: 28px;
  background: radial-gradient(circle at top left, rgba(99, 102, 241, 0.18), transparent 48%),
              linear-gradient(135deg, rgba(255, 255, 255, 0.98), rgba(238, 242, 255, 0.98));
  border: 1px solid rgba(99, 102, 241, 0.08);
}

.hero-illustration svg {
  position: relative;
  z-index: 1;
  width: 100%;
  height: 100%;
}

.nav-link {
  color: #4b5563;
}

.nav-link:hover {
  color: #4f46e5;
}

.menu-details summary {
  list-style: none;
}

.menu-details summary::-webkit-details-marker,
.nav-dropdown summary::-webkit-details-marker {
  display: none;
}

.nav-dropdown {
  position: relative;
}

.nav-dropdown-panel {
  position: absolute;
  top: calc(100% + 10px);
  left: 0;
  z-index: 30;
  width: 280px;
  border-radius: 22px;
  border: 1px solid rgba(99, 102, 241, 0.08);
  background: rgba(255, 255, 255, 0.98);
  box-shadow: 0 22px 40px -24px rgba(99, 102, 241, 0.3);
  padding: 14px;
}

.nav-dropdown-panel a {
  display: block;
  border-radius: 14px;
  padding: 10px 12px;
  font-size: 14px;
  color: #4b5563;
}

.nav-dropdown-panel a:hover {
  background: #eef2ff;
  color: #4f46e5;
}

.footer-link-list a:hover {
  color: #4f46e5;
}

.section-card {
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.section-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 16px 32px -24px rgba(99, 102, 241, 0.28);
}

.toc-link {
  display: block;
  border-radius: 14px;
  padding: 10px 12px;
  color: #475569;
}

.toc-link:hover {
  background: #eef2ff;
  color: #4f46e5;
}

@media (max-width: 1024px) {
  .hero-grid {
    grid-template-columns: 1fr;
  }

  .hero-illustration {
    min-height: 220px;
  }

  .nav-dropdown-panel {
    position: static;
    width: 100%;
    margin-top: 10px;
  }
}