/* ===== 背景文化电子书阅读器 ===== */

/* 书架视图 */
.bg-bookshelf {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  margin-bottom: 24px;
}
.bg-book-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 20px 12px;
  border-radius: 8px;
  border: 1px solid var(--border-ink, rgba(255,255,255,0.08));
  background: var(--bg-panel, rgba(20,20,30,0.4));
  text-decoration: none;
  cursor: pointer;
  transition: all 0.3s ease;
  backdrop-filter: blur(6px);
}
.bg-book-card:hover {
  border-color: var(--text-gold, var(--gold-dim, #8a7a4a));
  transform: translateY(-2px);
}
.bg-book-card__icon {
  font-size: 2rem;
  margin-bottom: 8px;
}
.bg-book-card__title {
  font-family: var(--font-kai, 'Noto Serif SC', serif);
  font-size: 1.1rem;
  letter-spacing: 3px;
  color: var(--text-primary);
  margin-bottom: 4px;
}
.bg-book-card__desc {
  font-size: 0.76rem;
  color: var(--text-muted);
}
.bg-book-card__count {
  font-size: 0.7rem;
  color: var(--text-gold, var(--gold-dim, #8a7a4a));
  margin-top: 6px;
}

/* 章节列表视图 */
.bg-chapter-list {
  display: none;
}
.bg-chapter-list.is-active {
  display: block;
}
.bg-chapter-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 16px;
  margin-bottom: 8px;
  border-radius: 6px;
  border: 1px solid var(--border-ink, rgba(255,255,255,0.06));
  background: var(--bg-panel, rgba(20,20,30,0.3));
  cursor: pointer;
  transition: all 0.2s ease;
  text-decoration: none;
}
.bg-chapter-item:hover {
  border-color: var(--text-gold, var(--gold-dim, #8a7a4a));
  background: rgba(138,122,74,0.06);
}
.bg-chapter-item__num {
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  border: 1px solid var(--text-gold, var(--gold-dim, #8a7a4a));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.78rem;
  color: var(--text-gold, var(--gold-dim, #8a7a4a));
  font-family: var(--font-kai, 'Noto Serif SC', serif);
}
.bg-chapter-item__title {
  font-family: var(--font-kai, 'Noto Serif SC', serif);
  font-size: 1rem;
  color: var(--text-primary);
  letter-spacing: 1px;
}

/* 阅读视图 */
.bg-reader {
  display: none;
}
.bg-reader.is-active {
  display: block;
}
.bg-reader__header {
  text-align: center;
  margin-bottom: 24px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-ink, rgba(255,255,255,0.08));
}
.bg-reader__title {
  font-family: var(--font-kai, 'Noto Serif SC', serif);
  font-size: 1.4rem;
  letter-spacing: 4px;
  color: var(--text-gold, var(--gold-dim, #8a7a4a));
  margin-bottom: 8px;
}
.bg-reader__source {
  font-size: 0.8rem;
  color: var(--text-muted);
  font-style: italic;
}

/* 原文区块 */
.bg-original {
  margin-bottom: 28px;
}
.bg-original__label {
  display: inline-block;
  font-family: var(--font-kai, 'Noto Serif SC', serif);
  font-size: 0.85rem;
  letter-spacing: 2px;
  color: var(--text-gold, var(--gold-dim, #8a7a4a));
  padding: 4px 12px;
  border: 1px solid var(--text-gold, var(--gold-dim, #8a7a4a));
  border-radius: 3px;
  margin-bottom: 14px;
}
.bg-original__text {
  font-family: var(--font-kai, 'Noto Serif SC', serif);
  font-size: 1rem;
  line-height: 2;
  color: var(--text-primary);
  white-space: pre-wrap;
  letter-spacing: 0.5px;
}

/* 白话解读区块 */
.bg-interpretation {
  margin-bottom: 28px;
  padding: 16px;
  border-radius: 6px;
  background: rgba(138,122,74,0.05);
  border: 1px solid var(--border-ink, rgba(255,255,255,0.06));
}
.bg-interpretation__label {
  display: inline-block;
  font-family: var(--font-kai, 'Noto Serif SC', serif);
  font-size: 0.85rem;
  letter-spacing: 2px;
  color: var(--text-gold, var(--gold-dim, #8a7a4a));
  padding: 4px 12px;
  border: 1px solid var(--text-gold, var(--gold-dim, #8a7a4a));
  border-radius: 3px;
  margin-bottom: 14px;
}
.bg-interpretation__text {
  font-family: var(--font-kai, 'Noto Serif SC', serif);
  font-size: 0.95rem;
  line-height: 1.9;
  color: var(--text-secondary, var(--text-muted));
  white-space: pre-wrap;
}

/* 翻页导航 */
.bg-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  margin: 28px 0 20px;
  padding-top: 20px;
  border-top: 1px solid var(--border-ink, rgba(255,255,255,0.08));
}
.bg-nav__btn {
  flex: 1;
  padding: 10px 16px;
  border: 1px solid var(--border-ink, rgba(255,255,255,0.1));
  border-radius: 6px;
  background: transparent;
  color: var(--text-muted);
  font-family: var(--font-kai, 'Noto Serif SC', serif);
  font-size: 0.88rem;
  cursor: pointer;
  transition: all 0.2s ease;
  text-align: center;
}
.bg-nav__btn:hover:not(:disabled) {
  border-color: var(--text-gold, var(--gold-dim, #8a7a4a));
  color: var(--text-gold, var(--gold-dim, #8a7a4a));
}
.bg-nav__btn:disabled {
  opacity: 0.3;
  cursor: default;
}
.bg-nav__btn--back {
  flex: 0 0 auto;
  padding: 10px 20px;
}

/* 回到顶部 */
.scroll-top-btn {
  position: fixed;
  right: 20px;
  bottom: 24px;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: 1px solid var(--border-ink, rgba(255,255,255,0.12));
  background: var(--bg-panel, rgba(20,20,30,0.85));
  color: var(--text-gold, var(--gold-dim, #8a7a4a));
  font-size: 1.3rem;
  cursor: pointer;
  opacity: 0;
  transform: translateY(10px);
  transition: all 0.3s ease;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  backdrop-filter: blur(8px);
}
.scroll-top-btn.is-visible {
  opacity: 1;
  transform: translateY(0);
}
.scroll-top-btn:hover {
  border-color: var(--text-gold, var(--gold-dim, #8a7a4a));
}

/* 移动端 */
@media (max-width: 480px) {
  .bg-bookshelf {
    gap: 10px;
  }
  .bg-book-card {
    padding: 16px 8px;
  }
  .bg-book-card__icon { font-size: 1.6rem; }
  .bg-book-card__title { font-size: 1rem; }
  .bg-reader__title { font-size: 1.2rem; }
  .bg-original__text { font-size: 0.92rem; line-height: 1.9; }
  .bg-interpretation__text { font-size: 0.88rem; line-height: 1.85; }
}

/* Parchment 主题 */
[data-theme="parchment"] .bg-book-card,
[data-theme="parchment"] .bg-chapter-item {
  background: rgba(243,234,216,0.5);
  border-color: rgba(90,70,40,0.15);
}
[data-theme="parchment"] .bg-interpretation {
  background: rgba(139,109,63,0.06);
  border-color: rgba(90,70,40,0.12);
}
[data-theme="parchment"] .scroll-top-btn {
  background: rgba(243,234,216,0.85);
  border-color: rgba(90,70,40,0.2);
  color: #8a6a2a;
}

/* Dark-Parchment 主题 */
[data-theme="dark-parchment"] .bg-book-card,
[data-theme="dark-parchment"] .bg-chapter-item {
  background: rgba(42,31,21,0.5);
  border-color: rgba(160,120,60,0.15);
}
[data-theme="dark-parchment"] .bg-interpretation {
  background: rgba(196,164,106,0.06);
  border-color: rgba(160,120,60,0.12);
}
[data-theme="dark-parchment"] .scroll-top-btn {
  background: rgba(42,31,21,0.85);
  border-color: rgba(160,120,60,0.2);
  color: #c4a46a;
}

/* ===== 书阁视图 ===== */
.bg-library {
  display: none;
}
.bg-library.is-active {
  display: block;
}
.bg-library__search-wrap {
  margin-bottom: 16px;
}
.bg-library__search {
  width: 100%;
  padding: 12px 16px;
  border-radius: 8px;
  border: 1px solid var(--border-ink, rgba(255,255,255,0.12));
  background: var(--bg-panel, rgba(20,20,30,0.4));
  color: var(--text-primary);
  font-size: 0.95rem;
  letter-spacing: 1px;
  outline: none;
  transition: border-color 0.2s ease;
  box-sizing: border-box;
}
.bg-library__search:focus {
  border-color: var(--text-gold, var(--gold-dim, #8a7a4a));
}
.bg-library__search::placeholder {
  color: var(--text-muted);
  opacity: 0.6;
}
.bg-library__grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  margin-bottom: 24px;
}
.bg-library-card {
  display: flex;
  flex-direction: column;
  padding: 16px 14px;
  border-radius: 8px;
  border: 1px solid var(--border-ink, rgba(255,255,255,0.08));
  background: var(--bg-panel, rgba(20,20,30,0.4));
  cursor: pointer;
  transition: all 0.3s ease;
  backdrop-filter: blur(6px);
}
.bg-library-card:hover {
  border-color: var(--text-gold, var(--gold-dim, #8a7a4a));
  transform: translateY(-2px);
}
.bg-library-card__title {
  font-family: var(--font-kai, 'Noto Serif SC', serif);
  font-size: 1.05rem;
  letter-spacing: 2px;
  color: var(--text-gold, var(--gold-dim, #8a7a4a));
  margin-bottom: 6px;
}
.bg-library-card__meta {
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-bottom: 6px;
}
.bg-library-card__desc {
  font-size: 0.82rem;
  color: var(--text-secondary, var(--text-muted));
  line-height: 1.6;
}
.bg-library__empty {
  text-align: center;
  padding: 40px 0;
  color: var(--text-muted);
  font-size: 1rem;
  letter-spacing: 2px;
  grid-column: 1 / -1;
}

/* ===== 书籍阅读视图 ===== */
.bg-book-reader {
  display: none;
}
.bg-book-reader.is-active {
  display: block;
}
.bg-book-reader__header {
  text-align: center;
  margin-bottom: 24px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-ink, rgba(255,255,255,0.08));
  position: relative;
}
.bg-book-reader__header button {
  position: absolute;
  left: 0;
  top: 0;
}
.bg-book-reader__title {
  font-family: var(--font-kai, 'Noto Serif SC', serif);
  font-size: 1.4rem;
  letter-spacing: 4px;
  color: var(--text-gold, var(--gold-dim, #8a7a4a));
  margin-bottom: 8px;
}
.bg-book-reader__meta {
  font-size: 0.8rem;
  color: var(--text-muted);
  font-style: italic;
}
.bg-book-reader__content {
  font-family: var(--font-kai, 'Noto Serif SC', serif);
  font-size: 1rem;
  line-height: 2;
  color: var(--text-primary);
  letter-spacing: 0.5px;
}
.bg-book-reader__content h1 {
  font-size: 1.3rem;
  color: var(--text-gold, var(--gold-dim, #8a7a4a));
  text-align: center;
  margin: 20px 0 16px;
  letter-spacing: 3px;
}
.bg-book-reader__content h2 {
  font-size: 1.1rem;
  color: var(--text-gold, var(--gold-dim, #8a7a4a));
  margin: 24px 0 12px;
  letter-spacing: 2px;
  border-bottom: 1px solid var(--border-ink, rgba(255,255,255,0.06));
  padding-bottom: 6px;
}
.bg-book-reader__content h3 {
  font-size: 1rem;
  color: var(--text-secondary, var(--text-primary));
  margin: 16px 0 8px;
}
.bg-book-reader__content p {
  margin-bottom: 14px;
}
.bg-book-reader__content blockquote {
  border-left: 3px solid var(--text-gold, var(--gold-dim, #8a7a4a));
  padding-left: 14px;
  margin: 12px 0;
  color: var(--text-secondary, var(--text-muted));
  font-size: 0.92rem;
}

/* 加载状态 */
.bg-loading {
  text-align: center;
  padding: 60px 0;
  color: var(--text-muted);
}
.bg-loading .spinner {
  width: 32px;
  height: 32px;
  border: 2px solid var(--border-ink, rgba(255,255,255,0.1));
  border-top-color: var(--text-gold, var(--gold-dim, #8a7a4a));
  border-radius: 50%;
  margin: 0 auto 12px;
  animation: bg-spin 0.8s linear infinite;
}
@keyframes bg-spin {
  to { transform: rotate(360deg); }
}

/* 书阁移动端 */
@media (max-width: 480px) {
  .bg-library__grid {
    gap: 10px;
  }
  .bg-library-card {
    padding: 12px 10px;
  }
  .bg-library-card__title { font-size: 0.95rem; }
  .bg-library-card__desc { font-size: 0.76rem; }
  .bg-book-reader__title { font-size: 1.2rem; }
  .bg-book-reader__content { font-size: 0.92rem; line-height: 1.9; }
}

/* 书阁 Parchment 主题 */
[data-theme="parchment"] .bg-library__search,
[data-theme="parchment"] .bg-library-card {
  background: rgba(243,234,216,0.5);
  border-color: rgba(90,70,40,0.15);
}
[data-theme="parchment"] .bg-library-card:hover {
  border-color: rgba(90,70,40,0.35);
}

/* 书阁 Dark-Parchment 主题 */
[data-theme="dark-parchment"] .bg-library__search,
[data-theme="dark-parchment"] .bg-library-card {
  background: rgba(42,31,21,0.5);
  border-color: rgba(160,120,60,0.15);
}
[data-theme="dark-parchment"] .bg-library-card:hover {
  border-color: rgba(160,120,60,0.35);
}