.sub-book-hero {
  display: grid;
  grid-template-columns: 1fr 1fr;
  min-height: 280px;
}

.sub-book-hero-text {
  padding: 48px 40px;
  background: var(--nav-dark-front);
  color: #fff;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.sub-book-hero-text h1 {
  font-family: var(--font-serif);
  font-size: 2rem;
  font-weight: 400;
  margin-bottom: 12px;
}

.sub-book-hero-text p {
  color: rgba(255, 255, 255, 0.7);
  font-size: 15px;
}

.sub-book-hero-visual {
  background-size: cover;
  background-position: center;
  min-height: 200px;
  max-width: 100%;
  overflow: hidden;
}

.sub-book-content {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 48px 20px 64px;
}

.sub-book-columns {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin: 32px 0;
}

.sub-book-col {
  padding: 24px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
}

.sub-book-col h3 {
  font-family: var(--font-serif);
  font-size: 1rem;
  margin-bottom: 12px;
  color: var(--primary);
}

.sub-book-col ul {
  list-style: none;
}

.sub-book-col li {
  font-size: 13px;
  color: var(--muted);
  padding: 6px 0;
  border-bottom: 1px solid var(--border);
}

.sub-book-col li:last-child {
  border-bottom: none;
}

.sub-book-content h2 {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  margin: 32px 0 14px;
  color: var(--text);
}

.sub-book-content p {
  font-size: 15px;
  color: var(--muted);
  margin-bottom: 14px;
  line-height: 1.65;
}

@media (max-width: 768px) {
  .sub-book-hero {
    grid-template-columns: 1fr;
  }

  .sub-book-hero-visual {
    min-height: 160px;
    max-width: 100vw;
  }

  .sub-book-columns {
    grid-template-columns: 1fr;
  }
}