.book-cover {
  background: #f8fafc;
  border: 1px solid #d1d5db;
  border-left: 6px solid #0f766e;
  margin: 1rem 0 2.75rem;
  padding: 2rem;
}

.cover-hero {
  align-items: stretch;
  display: grid;
  gap: 2rem;
  grid-template-columns: minmax(0, 1.55fr) minmax(17rem, 0.85fr);
}

.cover-main {
  min-width: 0;
}

.book-cover h1 {
  color: #111827;
  font-size: clamp(2.4rem, 6vw, 4.25rem);
  line-height: 1.05;
  margin: 0.4rem 0 1rem;
  letter-spacing: 0;
}

.book-kicker {
  color: #0f766e;
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  margin: 0;
  text-transform: uppercase;
}

.book-subtitle {
  color: #1f2937;
  font-size: 1.32rem;
  line-height: 1.55;
  max-width: 46rem;
}

.book-lede {
  color: #374151;
  font-size: 1.02rem;
  line-height: 1.7;
  max-width: 48rem;
}

.book-author {
  color: #111827;
  font-size: 1.05rem;
  line-height: 1.6;
  margin-top: 2rem;
}

.book-rights {
  color: #6b7280;
  font-size: 0.92rem;
  margin: 1.4rem 0 0;
}

.cover-signal {
  align-content: center;
  background: #ffffff;
  border: 1px solid #d1d5db;
  display: grid;
  gap: 0.85rem;
  justify-items: center;
  min-height: 18rem;
  padding: 1.3rem;
}

.signal-row {
  display: grid;
  gap: 0.55rem;
  width: 100%;
}

.signal-row span,
.signal-core {
  border: 1px solid #cbd5e1;
  color: #111827;
  display: block;
  font-size: 0.9rem;
  font-weight: 700;
  line-height: 1.2;
  padding: 0.7rem 0.8rem;
  text-align: center;
}

.signal-core {
  background: #0f766e;
  border-color: #0f766e;
  color: #ffffff;
  width: 100%;
}

.signal-flow {
  color: #64748b;
  font-size: 1.4rem;
  font-weight: 700;
  line-height: 1;
}

.cover-progress {
  border-top: 1px solid #d1d5db;
  display: grid;
  gap: 0.55rem;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  margin-top: 1.6rem;
  padding-top: 1rem;
}

.cover-progress span {
  color: #334155;
  font-size: 0.82rem;
  font-weight: 700;
  line-height: 1.25;
  text-align: center;
}

.promise-grid,
.reading-routes {
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin: 1.25rem 0 2rem;
}

.promise-grid > div,
.reading-routes > a {
  border: 1px solid #d1d5db;
  padding: 1rem;
}

.promise-grid h3 {
  color: #111827;
  font-size: 1rem;
  margin: 0 0 0.45rem;
}

.promise-grid p {
  color: #374151;
  font-size: 0.95rem;
  line-height: 1.55;
  margin: 0;
}

.reading-routes > a {
  color: #111827;
  display: block;
  text-decoration: none;
}

.reading-routes > a:hover {
  border-color: #0f766e;
}

.reading-routes strong {
  display: block;
  margin-bottom: 0.35rem;
}

.reading-routes span {
  color: #4b5563;
  display: block;
  font-size: 0.92rem;
  line-height: 1.5;
}

.definition-block {
  border-left: 4px solid #111827;
  margin: 1.5rem 0;
  padding: 0.2rem 0 0.2rem 1rem;
}

.definition-block strong {
  color: #111827;
}

@media (max-width: 900px) {
  .book-cover {
    padding: 1.4rem;
  }

  .cover-hero,
  .promise-grid,
  .reading-routes {
    grid-template-columns: 1fr;
  }

  .cover-signal {
    min-height: 0;
  }

  .cover-progress {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .cover-progress span {
    text-align: left;
  }
}