:root {
  --reading-primary: #4c5760;
  --reading-primary-light: #707b85;
  --reading-background: #f5f7fa;
}

.reading-hero {
  background: linear-gradient(135deg, rgba(76, 87, 96, 0.95), rgba(112, 123, 133, 0.9));
  color: #ffffff;
  border-radius: 1rem;
  padding: 3rem 2.5rem;
  margin-bottom: 2rem;
  box-shadow: 0 20px 45px rgba(76, 87, 96, 0.2);
}

.reading-hero h1 {
  font-weight: 700;
  letter-spacing: 0.5px;
}

.reading-section {
  background: #ffffff;
  border-radius: 1rem;
  padding: 1.5rem;
  box-shadow: 0 12px 32px rgba(76, 87, 96, 0.12);
  border: 1px solid rgba(76, 87, 96, 0.08);
}

.reading-section + .reading-section {
  margin-top: 2rem;
}

.reading-section__toggle {
  width: 100%;
  background: rgba(76, 87, 96, 0.08);
  border: 1px solid rgba(76, 87, 96, 0.18);
  border-radius: 0.85rem;
  padding: 0.85rem 1rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  color: var(--reading-primary);
  font-weight: 600;
  font-size: 1.05rem;
  transition: background-color 0.2s ease, border-color 0.2s ease, color 0.2s ease;
}

.reading-section__toggle:hover,
.reading-section__toggle:focus {
  background: rgba(76, 87, 96, 0.12);
  border-color: rgba(76, 87, 96, 0.28);
  color: var(--reading-primary);
  text-decoration: none;
  outline: none;
}

.reading-section__toggle:focus-visible {
  box-shadow: 0 0 0 0.25rem rgba(76, 87, 96, 0.2);
}

.reading-section__toggle-text {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

.reading-section__toggle-hint {
  font-size: 0.875rem;
  color: #6c7682;
  margin-left: auto;
}

.reading-section__toggle-hint::after {
  content: attr(data-label-closed);
}

.reading-section__toggle[aria-expanded="true"] .reading-section__toggle-hint::after {
  content: attr(data-label-open);
  color: var(--reading-primary);
}

.reading-section__icon {
  font-size: 1.1rem;
  transition: transform 0.2s ease;
}

.reading-section__toggle[aria-expanded="true"] .reading-section__icon {
  transform: rotate(180deg);
}

.reading-section__content {
  margin-top: 1.25rem;
}

.reading-section__inner {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.reading-section__actions .btn {
  min-width: 0;
}

.reading-group {
  background: #ffffff;
  border-radius: 1rem;
  padding: 1.5rem;
  box-shadow: 0 12px 30px rgba(76, 87, 96, 0.12);
  border: 1px solid rgba(76, 87, 96, 0.08);
}

.reading-group + .reading-group {
  margin-top: 1.5rem;
}

.reading-group__title {
  color: var(--reading-primary);
  font-weight: 600;
  margin-bottom: 0.75rem;
}

.reading-card {
  border: 1px solid rgba(76, 87, 96, 0.15);
  border-radius: 0.75rem;
  padding: 1rem 1.25rem;
  background: var(--reading-background);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  display: flex;
  flex-direction: column;
  --reading-card-cover-width: 96px;
}

@media (min-width: 768px) {
  .reading-card {
    --reading-card-cover-width: 96px;
  }
}

@media (min-width: 1200px) {
  .reading-card {
    --reading-card-cover-width: 96px;
  }
}

.reading-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 24px rgba(76, 87, 96, 0.18);
}

.reading-card__cover {
  border-radius: 0.65rem;
  overflow: hidden;
  background: linear-gradient(140deg, rgba(76, 87, 96, 0.08), rgba(76, 87, 96, 0.18));
  aspect-ratio: 2 / 3;
  display: flex;
  align-items: center;
  justify-content: center;
  width: min(var(--reading-card-cover-width), 100%);
  margin-inline: auto;
}

.reading-card__cover-image {
  width: 100%;
  height: auto;
  object-fit: contain;
  display: block;
}

.reading-card__cover-placeholder {
  font-size: 1.65rem;
  color: rgba(76, 87, 96, 0.35);
}

.reading-card--compact {
  --reading-card-cover-width: 96px;
}

@media (min-width: 768px) {
  .reading-card--compact {
    --reading-card-cover-width: 96px;
    flex-direction: row;
    align-items: flex-start;
    gap: 1.25rem;
  }

  .reading-card--compact .reading-card__cover {
    margin-inline: 0;
  }
}

@media (min-width: 1200px) {
  .reading-card--compact {
    --reading-card-cover-width: 96px;
  }
}

.reading-card--compact .reading-card__cover-placeholder {
  font-size: 1.35rem;
}

.reading-detail-book {
  width: 100%;
}

.reading-detail-book__cover {
  width: 110px;
  border-radius: 0.65rem;
  overflow: hidden;
  background: linear-gradient(140deg, rgba(76, 87, 96, 0.08), rgba(76, 87, 96, 0.18));
  flex-shrink: 0;
}

.reading-detail-book__cover-image {
  width: 100%;
  height: auto;
  display: block;
  object-fit: contain;
}

@media (min-width: 992px) {
  .reading-detail-book__cover {
    width: 128px;
  }
}

.reading-card__body {
  display: flex;
  flex-direction: column;
  flex: 1 1 auto;
}

.reading-card__title a {
  color: var(--reading-primary);
  text-decoration: none;
  font-weight: 600;
}

.reading-card__meta {
  font-size: 0.9rem;
  color: #596473;
}

.reading-card__footer {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: center;
  font-size: 0.85rem;
}

@media (max-width: 575.98px) {
  .reading-hero {
    padding: 2rem 1.5rem;
    text-align: center;
  }

  .reading-section {
    padding: 1rem;
  }

  .reading-section__toggle {
    font-size: 1rem;
    padding: 0.75rem 0.85rem;
  }

  .reading-section__toggle-hint {
    display: none;
  }

  .reading-section__icon {
    margin-left: auto;
  }

  .reading-section__intro {
    text-align: center;
  }

  .reading-section__actions {
    width: 100%;
  }

  .reading-section__actions .btn {
    width: 100%;
  }
}

@media (min-width: 576px) {
  .reading-section__actions .btn {
    width: auto;
  }
}

.reading-detail-header {
  background: #ffffff;
  border-radius: 1rem;
  padding: 2rem;
  box-shadow: 0 18px 36px rgba(76, 87, 96, 0.14);
  border: 1px solid rgba(76, 87, 96, 0.08);
  margin-bottom: 2rem;
}

.reading-detail-header h1 {
  color: var(--reading-primary);
  font-weight: 700;
}

.reading-detail-header__meta {
  color: #5e6975;
  font-size: 0.95rem;
}

.reading-section-title {
  color: var(--reading-primary);
  font-weight: 600;
  margin-bottom: 1rem;
}

.topic-card {
  border: 1px solid rgba(76, 87, 96, 0.12);
  border-radius: 0.75rem;
  padding: 1.25rem;
  background: #ffffff;
  box-shadow: 0 10px 22px rgba(76, 87, 96, 0.08);
}

.topic-card--locked {
  opacity: 0.6;
}

.topic-card__title a {
  color: var(--reading-primary);
  font-weight: 600;
  text-decoration: none;
}

.topic-card__meta {
  font-size: 0.85rem;
  color: #7a8592;
}

.reading-participants {
  background: #ffffff;
  border-radius: 1rem;
  padding: 1.5rem;
  box-shadow: 0 12px 30px rgba(76, 87, 96, 0.12);
  border: 1px solid rgba(76, 87, 96, 0.08);
}

.participant-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.75rem;
  background: rgba(76, 87, 96, 0.12);
  border-radius: 999px;
  color: var(--reading-primary);
  font-size: 0.85rem;
}

.discussion-thread {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.discussion-post {
  background: #ffffff;
  border: 1px solid rgba(76, 87, 96, 0.14);
  border-radius: 0.75rem;
  padding: 1.25rem;
  box-shadow: 0 10px 22px rgba(76, 87, 96, 0.1);
}

.discussion-post--nested {
  background: #fbfcfe;
}

.discussion-post__reply-meta {
  font-size: 0.85rem;
  color: #6c7682;
  display: flex;
  align-items: center;
  gap: 0.35rem;
  margin-bottom: 0.75rem;
}

.discussion-post__reply-meta a {
  color: inherit;
  font-weight: 600;
}

.discussion-post__reply-meta a:hover,
.discussion-post__reply-meta a:focus {
  color: var(--reading-primary);
  text-decoration: none;
}

.discussion-post__children {
  margin-top: 1rem;
  padding-left: 1.25rem;
  border-left: 2px solid rgba(76, 87, 96, 0.12);
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

@media (min-width: 768px) {
  .discussion-post__children {
    padding-left: 1.75rem;
  }
}

.discussion-post__reply-link {
  font-size: 0.9rem;
  color: var(--reading-primary);
}

.discussion-post__reply-link:hover,
.discussion-post__reply-link:focus {
  color: var(--reading-primary-light);
  text-decoration: none;
}

.discussion-post__author {
  font-weight: 600;
  color: var(--reading-primary);
}

.discussion-post__timestamp {
  font-size: 0.8rem;
  color: #7a8592;
}

.discussion-form textarea {
  border-color: rgba(76, 87, 96, 0.4);
}

.discussion-form__reply-preview {
  background-color: rgba(76, 87, 96, 0.08);
  border: 1px solid rgba(76, 87, 96, 0.15);
  border-radius: 0.75rem;
}

.discussion-form__quoted {
  max-height: 180px;
  overflow-y: auto;
  font-size: 0.9rem;
  color: rgba(33, 37, 41, 0.75);
}

.btn-reading {
  background-color: var(--reading-primary);
  border-color: var(--reading-primary);
  color: #ffffff;
}

.btn-reading:hover,
.btn-reading:focus {
  background-color: var(--reading-primary-light);
  border-color: var(--reading-primary-light);
  color: #ffffff;
}