.content-area {
  flex: 1;
  min-width: 0;
  padding: 2rem 2.5rem 4rem;
  position: relative;
  border-left: 2px solid var(--ink);
}
.content-section {
  margin-bottom: 3.5rem;
  scroll-margin-top: 80px;
  background: rgba(251, 248, 242, 0.4);
  padding: 1.5rem 1.5rem 2rem;
  border-radius: var(--radius);
}
.section-title {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1.8rem;
  padding: 0 0 0.8rem;
  border-bottom: 2px solid var(--ink);
}
.section-title .seal {
  flex-shrink: 0;
  width: 44px;
  height: 44px;
  border-radius: 4px;
  background: var(--accent);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 700;
  box-shadow: 0 0 0 3px rgba(192, 57, 43, 0.18);
}
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 42px;
  height: 42px;
  border-radius: 4px;
  background: var(--accent);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  cursor: pointer;
  border: none;
  box-shadow: var(--shadow-md);
  opacity: 0;
  transition: opacity 0.2s;
  pointer-events: none;
  z-index: 90;
}
.back-to-top.visible {
  opacity: 1;
  pointer-events: auto;
}
.back-to-top:hover {
  background: var(--accent-deep);
}
.placeholder-section {
  text-align: center;
  padding: 4rem 2rem;
}
.placeholder-section h2 {
  font-family: var(--font-display);
  font-size: 1.5rem;
  margin-bottom: 0.3rem;
}

.mobile-nav {
  display: flex;
  overflow-x: auto;
  gap: 0.3rem;
  padding: 0.7rem 1rem;
  background: var(--card);
  border-bottom: 2px solid var(--ink);
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}
.mobile-nav::-webkit-scrollbar {
  display: none;
}
.mobile-nav a {
  flex-shrink: 0;
  padding: 0.4rem 0.85rem;
  font-size: 0.8rem;
  font-weight: 700;
  font-family: var(--font-sans);
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  white-space: nowrap;
}
.mobile-nav a.active {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

@media (max-width: 900px) {
  .sidebar {
    display: none;
  }
  .content-area {
    padding: 1.25rem 0.75rem 3rem;
    border-left: none;
  }
  .content-section {
    padding-left: 0.5rem;
    padding-right: 0.5rem;
  }
}
@media (min-width: 901px) {
  .mobile-nav {
    display: none;
  }
}