/**
 * book.css - 图书样式文件
 * 定义图书视觉效果、翻页动画、书页质感
 * Requirements: 1.1, 1.2, 1.3, 1.4, 1.5, 3.1, 3.2, 3.3, 3.4
 */

/* ========================================
   应用容器
   ======================================== */

.app-container {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  padding: var(--spacing-lg);
  background: linear-gradient(135deg, 
    var(--color-paper-dark) 0%, 
    #D4C4A8 50%, 
    var(--color-paper-dark) 100%);
  /* 初始状态 - 用于加载后的入场动画 */
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

/* 内容就绪状态 - 加载完成后显示 */
.app-container.content-ready {
  opacity: 1;
  transform: translateY(0);
}

/* ========================================
   书籍容器
   ======================================== */

.book-container {
  position: relative;
  width: var(--book-width);
  max-width: 100%;
  perspective: 2000px;
  transform-style: preserve-3d;
}

/* ========================================
   加载动画 - 图书主题
   Requirements: 8.5
   ======================================== */

.loading-container {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  background: linear-gradient(135deg, 
    var(--color-paper) 0%, 
    var(--color-paper-dark) 50%, 
    var(--color-paper) 100%);
  z-index: var(--z-loading);
  transition: opacity 0.8s cubic-bezier(0.4, 0, 0.2, 1),
              transform 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

/* 淡出动画 - 平滑过渡到内容 */
.loading-container.fade-out {
  opacity: 0;
  transform: scale(1.05);
  pointer-events: none;
}

/* 书籍包装器 - 提供3D透视 */
.loading-book-wrapper {
  perspective: 800px;
  margin-bottom: var(--spacing-xl);
}

/* 书籍主体 */
.loading-book {
  position: relative;
  width: 120px;
  height: 160px;
  transform-style: preserve-3d;
  transform: rotateY(-15deg);
  animation: bookFloat 3s ease-in-out infinite;
}

@keyframes bookFloat {
  0%, 100% {
    transform: rotateY(-15deg) translateY(0);
  }
  50% {
    transform: rotateY(-15deg) translateY(-8px);
  }
}

/* 书脊 */
.loading-book-spine {
  position: absolute;
  left: 0;
  top: 0;
  width: 20px;
  height: 100%;
  background: linear-gradient(90deg,
    var(--color-accent-dark) 0%,
    var(--color-accent) 40%,
    var(--color-accent-light) 60%,
    var(--color-accent) 100%);
  transform: rotateY(-90deg) translateX(-10px);
  transform-origin: right center;
  border-radius: var(--radius-sm) 0 0 var(--radius-sm);
  box-shadow: inset -2px 0 4px rgba(0, 0, 0, 0.3);
}

/* 书籍封面 */
.loading-book-cover {
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(145deg,
    var(--color-accent) 0%,
    var(--color-accent-dark) 100%);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  transform-origin: left center;
  box-shadow: 
    4px 4px 15px var(--color-shadow-dark),
    inset 0 0 30px rgba(0, 0, 0, 0.1);
  display: flex;
  justify-content: center;
  align-items: center;
  overflow: hidden;
}

/* 封面装饰边框 */
.loading-book-cover::before {
  content: '';
  position: absolute;
  top: 10px;
  left: 10px;
  right: 10px;
  bottom: 10px;
  border: 1px solid var(--color-gold);
  border-radius: var(--radius-sm);
  opacity: 0.6;
}

/* 封面内部 */
.loading-book-cover-inner {
  text-align: center;
  z-index: 1;
}

/* 封面标题 - Requirements: 8.1, 8.2, 8.3 */
.loading-book-title {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-bold);
  color: var(--color-gold-light);
  text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.3);
  letter-spacing: 0.1em;
}

/* 翻动的书页容器 */
.loading-pages {
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
}

/* 翻动的书页 */
.loading-page {
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg,
    var(--color-paper-dark) 0%,
    var(--color-paper) 5%,
    var(--color-paper) 95%,
    var(--color-paper-dark) 100%);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  transform-origin: left center;
  backface-visibility: hidden;
  box-shadow: 
    2px 2px 8px var(--color-shadow-light),
    inset 0 0 20px rgba(0, 0, 0, 0.02);
}

/* 书页背面 */
.loading-page::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(270deg,
    var(--color-paper-dark) 0%,
    var(--color-paper-aged) 100%);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  transform: rotateY(180deg);
  backface-visibility: hidden;
}

/* 书页纹理线条 */
.loading-page::before {
  content: '';
  position: absolute;
  top: 20px;
  left: 15px;
  right: 15px;
  height: calc(100% - 40px);
  background: repeating-linear-gradient(
    0deg,
    transparent,
    transparent 8px,
    rgba(139, 69, 19, 0.05) 8px,
    rgba(139, 69, 19, 0.05) 9px
  );
  border-radius: var(--radius-sm);
}

/* 书页翻动动画 - 依次翻页效果 */
.loading-page-1 {
  animation: pageFlip 2.4s ease-in-out infinite;
  animation-delay: 0s;
  z-index: 4;
}

.loading-page-2 {
  animation: pageFlip 2.4s ease-in-out infinite;
  animation-delay: 0.3s;
  z-index: 3;
}

.loading-page-3 {
  animation: pageFlip 2.4s ease-in-out infinite;
  animation-delay: 0.6s;
  z-index: 2;
}

.loading-page-4 {
  animation: pageFlip 2.4s ease-in-out infinite;
  animation-delay: 0.9s;
  z-index: 1;
}

@keyframes pageFlip {
  0%, 20% {
    transform: rotateY(0deg);
    box-shadow: 2px 2px 8px var(--color-shadow-light);
  }
  35% {
    transform: rotateY(-60deg);
    box-shadow: -5px 5px 15px var(--color-shadow);
  }
  50% {
    transform: rotateY(-120deg);
    box-shadow: -8px 5px 20px var(--color-shadow-dark);
  }
  65% {
    transform: rotateY(-160deg);
    box-shadow: -3px 3px 10px var(--color-shadow);
  }
  80%, 100% {
    transform: rotateY(-180deg);
    box-shadow: 0 0 5px var(--color-shadow-light);
  }
}

/* 书页堆叠效果 - 模拟书籍厚度 */
.loading-book-pages-stack {
  position: absolute;
  left: 0;
  top: 5px;
  width: 100%;
  height: calc(100% - 10px);
  background: repeating-linear-gradient(
    90deg,
    var(--color-paper) 0px,
    var(--color-paper) 1px,
    var(--color-paper-dark) 1px,
    var(--color-paper-dark) 2px
  );
  transform: translateZ(-3px);
  border-radius: 0 2px 2px 0;
  box-shadow: inset 0 0 5px rgba(0, 0, 0, 0.1);
}

/* 加载文字 - Requirements: 8.1, 8.2, 8.3 */
.loading-text {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-normal);
  color: var(--color-ink-muted);
  margin-bottom: var(--spacing-md);
  letter-spacing: 0.05em;
  line-height: var(--line-height-normal);
}

/* 加载文字省略号动画 */
.loading-dots {
  display: inline-block;
  animation: dotsAnimation 1.5s steps(4, end) infinite;
  width: 1.5em;
  text-align: left;
  overflow: hidden;
  vertical-align: bottom;
}

@keyframes dotsAnimation {
  0% {
    content: '';
    width: 0;
  }
  25% {
    width: 0.5em;
  }
  50% {
    width: 1em;
  }
  75% {
    width: 1.5em;
  }
  100% {
    width: 0;
  }
}

/* 加载进度条 */
.loading-progress {
  width: 200px;
  height: 4px;
  background-color: var(--color-paper-dark);
  border-radius: var(--radius-sm);
  overflow: hidden;
  box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.1);
}

.loading-progress-bar {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg,
    var(--color-accent) 0%,
    var(--color-gold) 50%,
    var(--color-accent) 100%);
  background-size: 200% 100%;
  border-radius: var(--radius-sm);
  animation: progressAnimation 2s ease-in-out infinite,
             progressShimmer 1.5s linear infinite;
}

@keyframes progressAnimation {
  0% {
    width: 0%;
  }
  50% {
    width: 70%;
  }
  100% {
    width: 100%;
  }
}

@keyframes progressShimmer {
  0% {
    background-position: 200% 0;
  }
  100% {
    background-position: -200% 0;
  }
}

/* ========================================
   封面样式
   ======================================== */

.book-cover {
  position: relative;
  width: 100%;
  height: var(--book-height);
  display: flex;
  transform-style: preserve-3d;
}

/* 书脊 */
.cover-spine {
  width: var(--book-spine-width);
  height: 100%;
  background: linear-gradient(90deg,
    var(--color-accent-dark) 0%,
    var(--color-accent) 30%,
    var(--color-accent-light) 50%,
    var(--color-accent) 70%,
    var(--color-accent-dark) 100%);
  border-radius: var(--radius-sm) 0 0 var(--radius-sm);
  box-shadow: 
    inset -2px 0 4px rgba(0, 0, 0, 0.3),
    inset 2px 0 4px rgba(255, 255, 255, 0.1);
  flex-shrink: 0;
}

/* 封面正面 */
.cover-front {
  flex: 1;
  background: linear-gradient(145deg,
    var(--color-accent) 0%,
    var(--color-accent-dark) 100%);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  box-shadow: 
    4px 4px 20px var(--color-shadow-dark),
    inset 0 0 60px rgba(0, 0, 0, 0.1);
  display: flex;
  justify-content: center;
  align-items: center;
  position: relative;
  overflow: hidden;
}

/* 封面纹理效果 */
.cover-front::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-image: 
    repeating-linear-gradient(
      45deg,
      transparent,
      transparent 2px,
      rgba(255, 255, 255, 0.03) 2px,
      rgba(255, 255, 255, 0.03) 4px
    );
  pointer-events: none;
}

/* 封面边框装饰 */
.cover-front::after {
  content: '';
  position: absolute;
  top: 20px;
  left: 20px;
  right: 20px;
  bottom: 20px;
  border: 2px solid var(--color-gold);
  border-radius: var(--radius-sm);
  pointer-events: none;
}

/* 封面内容 - Requirements: 8.1, 8.2, 8.3 */
.cover-content {
  text-align: center;
  color: var(--color-paper);
  padding: var(--spacing-2xl);
  position: relative;
  z-index: 1;
}

.cover-title {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-4xl);
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
  margin-bottom: var(--spacing-lg);
  text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
  color: var(--color-gold-light);
}

.cover-subtitle {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--spacing-2xl);
  opacity: 0.9;
}

/* 封面装饰线 */
.cover-decoration {
  width: 120px;
  height: 3px;
  background: linear-gradient(90deg,
    transparent 0%,
    var(--color-gold) 20%,
    var(--color-gold) 80%,
    transparent 100%);
  margin: 0 auto var(--spacing-2xl);
}

/* 进入按钮 - Requirements: 8.1, 8.2, 8.3, 8.4 */
.cover-enter-btn {
  background-color: var(--color-paper);
  color: var(--color-accent);
  padding: var(--spacing-md) var(--spacing-2xl);
  font-family: var(--font-family-sans);
  font-size: var(--font-size-md);
  font-weight: var(--font-weight-semibold);
  line-height: var(--line-height-normal);
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: all var(--transition-normal);
  min-height: var(--touch-target-min);
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
  letter-spacing: 0.02em;
}

.cover-enter-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
  background-color: var(--color-gold-light);
  color: var(--color-ink);
}

.cover-enter-btn:active {
  transform: translateY(0);
}

/* ========================================
   目录页样式
   ======================================== */

.book-toc {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--book-height);
  background-color: var(--color-paper);
  border-radius: var(--radius-md);
  box-shadow: 0 10px 40px var(--color-shadow-dark);
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.toc-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-lg) var(--spacing-xl);
  border-bottom: 1px solid var(--border-color-light);
  background-color: var(--color-paper-light);
  flex-shrink: 0;
}

.toc-header h2 {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-accent);
  margin: 0;
  line-height: var(--line-height-tight);
}

.toc-close-btn {
  background-color: transparent;
  color: var(--color-ink-muted);
  padding: var(--spacing-sm) var(--spacing-md);
  font-family: var(--font-family-sans);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-normal);
  border: 1px solid var(--border-color-light);
  border-radius: var(--radius-sm);
  min-height: var(--touch-target-min);
  min-width: var(--touch-target-min);
  line-height: var(--line-height-normal);
}

.toc-close-btn:hover {
  background-color: var(--color-paper-dark);
  color: var(--color-ink);
}

.toc-content {
  flex: 1;
  overflow-y: auto;
  padding: var(--spacing-lg) var(--spacing-xl);
  /* 确保内容可以滚动 - 需要明确的高度约束 */
  min-height: 0;
}

/* 目录分类 - Requirements: 8.1, 8.2, 8.3 */
.toc-section {
  margin-bottom: var(--spacing-xl);
}

.toc-section-title {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-accent);
  margin-bottom: var(--spacing-md);
  padding-bottom: var(--spacing-sm);
  border-bottom: 2px solid var(--color-accent);
  display: inline-block;
  line-height: var(--line-height-tight);
}

.toc-chapter-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.toc-chapter-item {
  margin-bottom: var(--spacing-sm);
}

.toc-chapter-link {
  display: flex;
  align-items: baseline;
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-sm);
  transition: background-color var(--transition-fast);
  text-decoration: none;
  min-height: var(--touch-target-min);
}

.toc-chapter-link:hover {
  background-color: var(--color-paper-dark);
  text-decoration: none;
}

.toc-chapter-number {
  font-family: var(--font-family-sans);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-normal);
  color: var(--color-ink-muted);
  min-width: 50px;
  flex-shrink: 0;
  line-height: var(--line-height-normal);
}

.toc-chapter-title {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  color: var(--color-ink);
  flex: 1;
  line-height: var(--line-height-normal);
}

.toc-chapter-subtitle {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-normal);
  color: var(--color-ink-faded);
  margin-left: var(--spacing-sm);
  line-height: var(--line-height-normal);
}

/* 已读标记 - Requirements: 7.4 */
.toc-chapter-link.is-read {
  position: relative;
}

/* 已读章节的勾选标记 */
.toc-chapter-link.is-read .toc-chapter-number::before {
  content: '✓ ';
  color: var(--color-success);
  font-weight: var(--font-weight-bold);
}

/* 已读章节的标题样式 */
.toc-chapter-link.is-read .toc-chapter-title {
  color: var(--color-ink-muted);
}

/* 已读章节的副标题样式 */
.toc-chapter-link.is-read .toc-chapter-subtitle {
  color: var(--color-ink-faded);
}

/* 已读章节悬停效果 */
.toc-chapter-link.is-read:hover {
  background-color: var(--color-paper-dark);
}

.toc-chapter-link.is-read:hover .toc-chapter-title {
  color: var(--color-ink);
}

/* ========================================
   内容页样式
   Requirements: 5.4 - 支持触摸滑动翻页手势
   ======================================== */

.book-content {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--book-height);
  display: flex;
  background-color: var(--color-paper);
  border-radius: var(--radius-md);
  box-shadow: 0 10px 40px var(--color-shadow-dark);
  overflow: hidden;
  /* 触摸手势优化 - Requirement 5.4 */
  touch-action: pan-y pinch-zoom;
}

/* 单页样式 - 增强书页质感 */
.page {
  flex: 1;
  position: relative;
  background-color: var(--color-paper);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  /* 书页内部微妙的阴影 */
  box-shadow: inset 0 0 30px rgba(0, 0, 0, 0.02);
}

.page-left {
  border-right: 1px solid var(--border-color-light);
  /* 左页特有的阴影 - 模拟书脊处的阴影 */
  box-shadow: 
    inset -10px 0 20px rgba(0, 0, 0, 0.03),
    inset 0 0 30px rgba(0, 0, 0, 0.02);
}

.page-right {
  /* 右页特有的阴影 - 模拟书脊处的阴影 */
  box-shadow: 
    inset 10px 0 20px rgba(0, 0, 0, 0.03),
    inset 0 0 30px rgba(0, 0, 0, 0.02);
}

/* 书页内部 */
.page-inner {
  height: 100%;
  display: flex;
  flex-direction: column;
  padding: var(--padding-page);
  position: relative;
  overflow: hidden;
}

/* 书页纹理 - 模拟真实纸张质感 */
.page::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  /* 多层纹理叠加：边缘阴影 + 纸张纤维纹理 + 细微噪点 */
  background-image: 
    /* 边缘渐变阴影 - 模拟书页弯曲 */
    linear-gradient(90deg, 
      rgba(0, 0, 0, 0.05) 0%, 
      transparent 3%, 
      transparent 97%, 
      rgba(0, 0, 0, 0.05) 100%),
    /* 纸张纤维纹理 - 水平方向 */
    repeating-linear-gradient(
      0deg,
      transparent,
      transparent 2px,
      rgba(139, 69, 19, 0.01) 2px,
      rgba(139, 69, 19, 0.01) 4px
    ),
    /* 纸张纤维纹理 - 垂直方向 */
    repeating-linear-gradient(
      90deg,
      transparent,
      transparent 3px,
      rgba(139, 69, 19, 0.008) 3px,
      rgba(139, 69, 19, 0.008) 6px
    );
  pointer-events: none;
  z-index: 1;
}

/* 书页额外纹理层 - 模拟纸张老化效果 */
.page::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  /* 轻微的渐变色调，模拟纸张不均匀的颜色 */
  background: 
    radial-gradient(
      ellipse at 30% 20%,
      rgba(255, 248, 235, 0.3) 0%,
      transparent 50%
    ),
    radial-gradient(
      ellipse at 70% 80%,
      rgba(232, 224, 208, 0.2) 0%,
      transparent 40%
    );
  pointer-events: none;
  z-index: 0;
}

/* 书页内容区域 */
.page-content {
  flex: 1;
  overflow-y: auto;
  overflow-x: hidden;
  padding-right: var(--spacing-sm);
  /* 确保内容可以滚动 - 需要明确的高度约束 */
  min-height: 0;
  /* 滚动条样式优化 */
  scrollbar-width: thin;
  scrollbar-color: var(--color-ink-faded) transparent;
}

/* 章节标题样式 - Requirements: 8.1, 8.2, 8.3 */
.chapter-header {
  text-align: center;
  margin-bottom: var(--spacing-2xl);
  padding-bottom: var(--spacing-lg);
  border-bottom: 1px solid var(--border-color-light);
}

.chapter-number {
  font-family: var(--font-family-sans);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-normal);
  color: var(--color-ink-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: var(--spacing-sm);
  line-height: var(--line-height-normal);
}

.chapter-title {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-accent);
  margin-bottom: var(--spacing-sm);
  line-height: var(--line-height-tight);
}

.chapter-subtitle {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-md);
  font-weight: var(--font-weight-normal);
  color: var(--color-ink-muted);
  font-style: italic;
  line-height: var(--line-height-normal);
}

/* 页脚 - Requirements: 8.1, 8.2, 8.3 */
.page-footer {
  display: flex;
  justify-content: center;
  padding-top: var(--spacing-md);
  border-top: 1px solid var(--border-color-light);
  margin-top: auto;
  flex-shrink: 0;
}

.page-number {
  font-family: var(--font-family-sans);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-normal);
  color: var(--color-ink-muted);
  line-height: var(--line-height-normal);
}

/* 书页边缘厚度效果 - 模拟书页堆叠 */
.page-edge {
  position: absolute;
  top: 0;
  bottom: 0;
  width: var(--page-thickness);
  /* 多层渐变模拟书页厚度 */
  background: 
    /* 主要厚度渐变 */
    linear-gradient(90deg,
      var(--color-paper-dark) 0%,
      var(--color-paper) 40%,
      var(--color-paper-light) 50%,
      var(--color-paper) 60%,
      var(--color-paper-dark) 100%),
    /* 细线条模拟多页堆叠 */
    repeating-linear-gradient(
      0deg,
      transparent,
      transparent 3px,
      rgba(0, 0, 0, 0.02) 3px,
      rgba(0, 0, 0, 0.02) 4px
    );
}

.page-left .page-edge {
  right: 0;
  /* 左页右边缘阴影 - 向内凹陷效果 */
  box-shadow: 
    inset -2px 0 4px rgba(0, 0, 0, 0.15),
    inset -1px 0 1px rgba(0, 0, 0, 0.1),
    1px 0 2px rgba(0, 0, 0, 0.05);
}

.page-right .page-edge {
  left: 0;
  /* 右页左边缘阴影 - 向内凹陷效果 */
  box-shadow: 
    inset 2px 0 4px rgba(0, 0, 0, 0.15),
    inset 1px 0 1px rgba(0, 0, 0, 0.1),
    -1px 0 2px rgba(0, 0, 0, 0.05);
}

/* ========================================
   导航控制样式
   ======================================== */

.book-navigation {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: var(--z-dropdown);
}

/* 导航按钮 
   Requirements: 5.5, 8.1, 8.2, 8.3, 8.4
   Property 8: 触摸区域最小尺寸
   For any 导航按钮元素，其可点击区域的宽度和高度都应不小于44px。
*/
.nav-btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: var(--touch-target-min);
  height: 80px;
  min-height: var(--touch-target-min);  /* 确保最小高度44px - Requirement 5.5 */
  min-width: var(--touch-target-min);   /* 确保最小宽度44px - Requirement 5.5 */
  background-color: var(--color-paper);
  border: 1px solid var(--border-color-light);
  border-radius: var(--radius-md);
  cursor: pointer;
  pointer-events: auto;
  display: flex;
  justify-content: center;
  align-items: center;
  transition: all var(--transition-fast);
  box-shadow: 0 2px 8px var(--color-shadow-light);
  /* 触摸优化 */
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
  font-family: var(--font-family-sans);
}

.nav-btn:hover:not(:disabled) {
  background-color: var(--color-accent);
  color: var(--color-paper);
  box-shadow: 0 4px 12px var(--color-shadow);
}

.nav-btn:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

.nav-prev {
  left: -60px;
}

.nav-next {
  right: -60px;
}

.nav-icon {
  font-family: var(--font-family-sans);
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  line-height: 1;
}

/* 导航信息栏 - Requirements: 8.1, 8.2, 8.3 */
.nav-info {
  position: absolute;
  bottom: -50px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  pointer-events: auto;
}

.nav-toc-btn {
  background-color: var(--color-paper);
  color: var(--color-ink-muted);
  padding: var(--spacing-sm) var(--spacing-md);
  font-family: var(--font-family-sans);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-normal);
  border: 1px solid var(--border-color-light);
  border-radius: var(--radius-sm);
  min-height: var(--touch-target-min);
  min-width: var(--touch-target-min);
  line-height: var(--line-height-normal);
}

.nav-toc-btn:hover {
  background-color: var(--color-paper-dark);
  color: var(--color-ink);
}

.nav-chapter {
  font-family: var(--font-family-sans);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-normal);
  color: var(--color-ink-muted);
  line-height: var(--line-height-normal);
}

/* ========================================
   翻页动画
   ======================================== */

/* 翻页容器 */
.page-flip-container {
  position: absolute;
  top: 0;
  left: 50%;
  width: 50%;
  height: 100%;
  transform-style: preserve-3d;
  transform-origin: left center;
  z-index: var(--z-sticky);
  pointer-events: none;
}

/* 向右翻页时的容器位置调整 */
.page-flip-container.flip-to-right {
  left: 0;
  transform-origin: right center;
}

/* 翻页中的页面 */
.page-flipping {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  background-color: var(--color-paper);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  overflow: hidden;
  /* 增强3D效果 */
  transform-style: preserve-3d;
}

/* 页面正面 */
.page-flipping-front {
  transform: rotateY(0deg);
  /* 纸张纹理 */
  background: 
    linear-gradient(90deg, 
      rgba(0, 0, 0, 0.03) 0%, 
      transparent 5%, 
      transparent 95%, 
      rgba(0, 0, 0, 0.02) 100%),
    var(--color-paper);
}

/* 页面背面 */
.page-flipping-back {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  transform: rotateY(180deg);
  background: 
    linear-gradient(270deg, 
      rgba(0, 0, 0, 0.05) 0%, 
      transparent 8%),
    var(--color-paper-dark);
  backface-visibility: hidden;
}

/* 向左翻页动画（下一页） */
.flip-to-left {
  animation: flipToLeft var(--transition-page-flip) cubic-bezier(0.645, 0.045, 0.355, 1) forwards;
}

@keyframes flipToLeft {
  0% {
    transform: rotateY(0deg) scale(1);
    box-shadow: 0 0 10px var(--color-shadow-light);
  }
  25% {
    transform: rotateY(-45deg) scale(1.02);
    box-shadow: -5px 5px 20px var(--color-shadow);
  }
  50% {
    transform: rotateY(-90deg) scale(1.03);
    box-shadow: -10px 5px 30px var(--color-shadow-dark);
  }
  75% {
    transform: rotateY(-135deg) scale(1.02);
    box-shadow: -5px 5px 20px var(--color-shadow);
  }
  100% {
    transform: rotateY(-180deg) scale(1);
    box-shadow: 0 0 10px var(--color-shadow-light);
  }
}

/* 向右翻页动画（上一页） */
.flip-to-right {
  animation: flipToRight var(--transition-page-flip) cubic-bezier(0.645, 0.045, 0.355, 1) forwards;
}

@keyframes flipToRight {
  0% {
    transform: rotateY(-180deg) scale(1);
    box-shadow: 0 0 10px var(--color-shadow-light);
  }
  25% {
    transform: rotateY(-135deg) scale(1.02);
    box-shadow: 5px 5px 20px var(--color-shadow);
  }
  50% {
    transform: rotateY(-90deg) scale(1.03);
    box-shadow: 10px 5px 30px var(--color-shadow-dark);
  }
  75% {
    transform: rotateY(-45deg) scale(1.02);
    box-shadow: 5px 5px 20px var(--color-shadow);
  }
  100% {
    transform: rotateY(0deg) scale(1);
    box-shadow: 0 0 10px var(--color-shadow-light);
  }
}

/* 页面弯曲效果 - 增强版 */
.page-curl {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  opacity: 0;
  transition: opacity var(--transition-fast);
}

/* 弯曲阴影效果 - 模拟纸张弯曲时的光影变化 */
.page-curl::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  /* 动态阴影渐变 - 模拟弯曲时的明暗变化 */
  background: linear-gradient(
    to right,
    transparent 0%,
    rgba(0, 0, 0, 0.03) 30%,
    rgba(0, 0, 0, 0.08) 50%,
    rgba(0, 0, 0, 0.15) 70%,
    rgba(0, 0, 0, 0.25) 85%,
    rgba(0, 0, 0, 0.35) 100%
  );
}

/* 弯曲高光效果 - 模拟纸张弯曲处的反光 */
.page-curl::after {
  content: '';
  position: absolute;
  top: 0;
  right: 0;
  width: 30%;
  height: 100%;
  /* 高光渐变 */
  background: linear-gradient(
    to left,
    rgba(255, 255, 255, 0.15) 0%,
    rgba(255, 255, 255, 0.08) 30%,
    transparent 100%
  );
}

.page-flipping .page-curl {
  opacity: 1;
  animation: curlEffect var(--transition-page-flip) ease-in-out;
}

@keyframes curlEffect {
  0% {
    opacity: 0;
  }
  20% {
    opacity: 0.5;
  }
  50% {
    opacity: 1;
  }
  80% {
    opacity: 0.5;
  }
  100% {
    opacity: 0;
  }
}

/* 翻页时的页面边缘弯曲效果 */
.page-flipping.curling {
  /* 使用 CSS filter 模拟轻微的弯曲变形 */
  filter: drop-shadow(-2px 0 3px rgba(0, 0, 0, 0.1));
}

/* 移动端滑动动画 */
.page-slide-left {
  animation: slideOutLeft 0.3s ease-out forwards;
}

.page-slide-right {
  animation: slideOutRight 0.3s ease-out forwards;
}

.page-slide-in-left {
  animation: slideInLeft 0.3s ease-out forwards;
}

.page-slide-in-right {
  animation: slideInRight 0.3s ease-out forwards;
}

@keyframes slideOutLeft {
  0% {
    transform: translateX(0);
    opacity: 1;
  }
  100% {
    transform: translateX(-100%);
    opacity: 0;
  }
}

@keyframes slideOutRight {
  0% {
    transform: translateX(0);
    opacity: 1;
  }
  100% {
    transform: translateX(100%);
    opacity: 0;
  }
}

@keyframes slideInLeft {
  0% {
    transform: translateX(100%);
    opacity: 0;
  }
  100% {
    transform: translateX(0);
    opacity: 1;
  }
}

@keyframes slideInRight {
  0% {
    transform: translateX(-100%);
    opacity: 0;
  }
  100% {
    transform: translateX(0);
    opacity: 1;
  }
}

/* ========================================
   继续阅读弹窗
   ======================================== */

.continue-reading-modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: var(--z-modal);
}

.continue-reading-modal .modal-content {
  background-color: var(--color-paper);
  padding: var(--spacing-2xl);
  border-radius: var(--radius-lg);
  text-align: center;
  max-width: 400px;
  box-shadow: 0 10px 40px var(--color-shadow-dark);
}

.continue-reading-modal p {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  text-indent: 0;
  text-align: center;
  line-height: var(--line-height-normal);
  color: var(--color-ink);
}

.continue-reading-modal .modal-chapter {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-accent);
  margin-bottom: var(--spacing-xl);
  line-height: var(--line-height-normal);
}

.modal-buttons {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
}

.modal-btn {
  padding: var(--spacing-md) var(--spacing-xl);
  font-family: var(--font-family-sans);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
  border-radius: var(--radius-md);
  min-height: var(--touch-target-min);
  min-width: 100px;
  line-height: var(--line-height-normal);
  letter-spacing: 0.02em;
}

.modal-btn-primary {
  background-color: var(--color-accent);
  color: var(--color-paper);
  border: none;
}

.modal-btn-primary:hover {
  background-color: var(--color-accent-dark);
}

.modal-btn-secondary {
  background-color: transparent;
  color: var(--color-ink-muted);
  border: 1px solid var(--border-color-light);
}

.modal-btn-secondary:hover {
  background-color: var(--color-paper-dark);
}

/* ========================================
   内容样式增强
   ======================================== */

/* 重点提示框 - Requirements: 8.1, 8.2, 8.3 */
.highlight-box {
  background-color: var(--color-paper-aged);
  border-left: 4px solid var(--color-accent);
  padding: var(--spacing-md);
  margin: var(--spacing-lg) 0;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-family: var(--font-family-serif);
  font-size: var(--font-size-base);
  line-height: var(--line-height-relaxed);
}

/* 注释说明 - Requirements: 8.1, 8.2, 8.3 */
.note {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-normal);
  font-style: italic;
  color: var(--color-ink-muted);
  padding: var(--spacing-sm);
  background-color: var(--color-paper-light);
  border-radius: var(--radius-sm);
  line-height: var(--line-height-relaxed);
}

/* 图片容器 - Requirements: 8.3 */
.image-container {
  margin: var(--spacing-xl) 0;
  text-align: center;
}

.image-container img {
  max-width: 100%;
  border-radius: var(--radius-sm);
  box-shadow: 0 4px 12px var(--color-shadow-light);
}

.image-caption {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-normal);
  font-style: italic;
  color: var(--color-ink-muted);
  margin-top: var(--spacing-sm);
  line-height: var(--line-height-normal);
}


/* ========================================
   章节内容渲染样式
   Requirements: 4.1, 4.2, 4.3, 4.4, 8.1, 8.2, 8.3
   ======================================== */

/* 章节容器 */
.chapter-container {
  max-width: 100%;
}

/* 章节头部增强 */
.chapter-header {
  text-align: center;
  margin-bottom: var(--spacing-2xl);
  padding-bottom: var(--spacing-lg);
  border-bottom: 1px solid var(--border-color-light);
  position: relative;
}

.chapter-header::after {
  content: '';
  position: absolute;
  bottom: -1px;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 3px;
  background-color: var(--color-accent);
}

/* 章节分类标签 - Requirements: 8.1, 8.2, 8.3 */
.chapter-section-tag {
  display: inline-block;
  font-family: var(--font-family-sans);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-medium);
  color: var(--color-paper);
  background-color: var(--color-accent);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-sm);
  margin-top: var(--spacing-md);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  line-height: var(--line-height-normal);
}

/* 章节正文 - Requirements: 8.1, 8.2, 8.3 */
.chapter-body {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-relaxed);
  color: var(--color-ink);
}

.chapter-body p {
  margin-bottom: var(--margin-paragraph);
  text-align: justify;
  text-indent: 2em;
}

/* 章节段落 - Requirements: 8.2, 8.3 */
.chapter-paragraph {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  margin-bottom: var(--margin-paragraph);
  text-align: justify;
  text-indent: 2em;
  line-height: var(--line-height-relaxed);
  color: var(--color-ink);
}

/* 占位内容样式 - Requirements: 8.1, 8.2, 8.3 */
.chapter-placeholder {
  text-align: center;
  padding: var(--spacing-3xl) var(--spacing-xl);
  color: var(--color-ink-muted);
}

.placeholder-text {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-normal);
  margin-bottom: var(--spacing-md);
  text-indent: 0;
  line-height: var(--line-height-normal);
}

.placeholder-hint {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-normal);
  font-style: italic;
  text-indent: 0;
  line-height: var(--line-height-normal);
}

/* ========================================
   代码块样式 - Requirements: 4.2, 8.2
   ======================================== */

/* 代码块容器 */
.code-block-container {
  position: relative;
  margin: var(--spacing-lg) 0;
  border-radius: var(--radius-md);
  overflow: hidden;
}

/* 语言标签 */
.code-language-label {
  position: absolute;
  top: 0;
  right: 0;
  font-family: var(--font-family-mono);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-medium);
  color: var(--color-paper-dark);
  background-color: var(--color-ink-muted);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: 0 var(--radius-md) 0 var(--radius-sm);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  line-height: var(--line-height-normal);
}

/* 代码块 */
.code-block {
  font-family: var(--font-family-mono);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-normal);
  line-height: 1.6;
  background-color: var(--color-ink);
  color: var(--color-paper);
  padding: var(--spacing-lg);
  border-radius: var(--radius-md);
  overflow-x: auto;
  margin: 0;
  /* 代码块不需要首行缩进 */
  text-indent: 0;
  white-space: pre;
  tab-size: 2;
}

.code-block code {
  font-family: var(--font-family-mono);
  font-weight: var(--font-weight-normal);
  background-color: transparent;
  padding: 0;
  color: inherit;
  font-size: inherit;
}

/* 行内代码 */
.inline-code,
code:not(pre code):not(.code-block code) {
  font-family: var(--font-family-mono);
  font-size: 0.9em;
  font-weight: var(--font-weight-normal);
  background-color: var(--color-paper-dark);
  color: var(--color-accent-dark);
  padding: 0.15em 0.4em;
  border-radius: var(--radius-sm);
  white-space: nowrap;
}

/* 代码块内的语法高亮（基础） */
.code-block .keyword {
  color: #ff79c6;
}

.code-block .string {
  color: #f1fa8c;
}

.code-block .comment {
  color: #6272a4;
  font-style: italic;
}

.code-block .number {
  color: #bd93f9;
}

.code-block .function {
  color: #50fa7b;
}

/* ========================================
   图片样式 - Requirements: 4.3, 8.3
   ======================================== */

/* 图片容器 */
.chapter-figure {
  margin: var(--spacing-xl) 0;
  text-align: center;
}

/* 章节图片 */
.chapter-image {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-md);
  box-shadow: 0 4px 16px var(--color-shadow);
  transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.chapter-image:hover {
  transform: scale(1.02);
  box-shadow: 0 8px 24px var(--color-shadow-dark);
}

/* 图片说明 - Requirements: 8.2, 8.3 */
.chapter-figcaption {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-normal);
  font-style: italic;
  color: var(--color-ink-muted);
  margin-top: var(--spacing-sm);
  text-indent: 0;
  line-height: var(--line-height-normal);
}

/* 图片加载错误 */
.chapter-image.image-error {
  min-height: 100px;
  background-color: var(--color-paper-dark);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-ink-muted);
  font-family: var(--font-family-serif);
  font-style: italic;
}

/* ========================================
   层级结构样式 - Requirements: 4.4, 8.1, 8.2, 8.3
   ======================================== */

/* 小节标题 */
.chapter-section-title {
  font-family: var(--font-family-serif);
  margin-top: var(--spacing-xl);
  margin-bottom: var(--spacing-md);
  color: var(--color-ink);
  position: relative;
  padding-left: var(--spacing-md);
  line-height: var(--line-height-tight);
}

.chapter-section-title::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 4px;
  height: 80%;
  background-color: var(--color-accent);
  border-radius: var(--radius-sm);
}

.chapter-h2 {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
}

.chapter-h3 {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
}

.chapter-h4 {
  font-size: var(--font-size-md);
  font-weight: var(--font-weight-semibold);
}

.chapter-h5 {
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
}

.chapter-h6 {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
}

/* 章节正文中的标题 - Requirements: 8.1, 8.2, 8.3 */
.chapter-body h2,
.chapter-body h3,
.chapter-body h4,
.chapter-body h5,
.chapter-body h6 {
  font-family: var(--font-family-serif);
  margin-top: var(--spacing-xl);
  margin-bottom: var(--spacing-md);
  color: var(--color-ink);
  position: relative;
  padding-left: var(--spacing-md);
  line-height: var(--line-height-tight);
}

.chapter-body h2::before,
.chapter-body h3::before,
.chapter-body h4::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 4px;
  height: 70%;
  background-color: var(--color-accent);
  border-radius: var(--radius-sm);
}

.chapter-body h2 {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
}

.chapter-body h3 {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
}

.chapter-body h4 {
  font-size: var(--font-size-md);
  font-weight: var(--font-weight-semibold);
}

/* ========================================
   提示框/注释框样式 - Requirements: 8.1, 8.2, 8.3
   ======================================== */

.chapter-note {
  margin: var(--spacing-lg) 0;
  padding: var(--spacing-md);
  border-radius: var(--radius-md);
  border-left: 4px solid;
  font-family: var(--font-family-serif);
}

.chapter-note-tip {
  background-color: rgba(74, 124, 89, 0.1);
  border-left-color: var(--color-success);
}

.chapter-note-note {
  background-color: rgba(139, 69, 19, 0.1);
  border-left-color: var(--color-accent);
}

.chapter-note-warning {
  background-color: rgba(184, 134, 11, 0.1);
  border-left-color: var(--color-warning);
}

.chapter-note-example {
  background-color: rgba(93, 78, 55, 0.1);
  border-left-color: var(--color-link);
}

.note-label {
  display: block;
  font-family: var(--font-family-sans);
  font-weight: var(--font-weight-semibold);
  font-size: var(--font-size-sm);
  margin-bottom: var(--spacing-sm);
  line-height: var(--line-height-normal);
}

.note-content {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-relaxed);
  color: var(--color-ink);
}

.note-content p {
  text-indent: 0;
  margin-bottom: var(--spacing-sm);
}

.note-content p:last-child {
  margin-bottom: 0;
}

/* ========================================
   列表样式 - Requirements: 8.2, 8.3
   ======================================== */

.chapter-list {
  margin: var(--spacing-md) 0;
  padding-left: var(--spacing-xl);
  font-family: var(--font-family-serif);
}

.chapter-list-item {
  margin-bottom: var(--spacing-sm);
  line-height: var(--line-height-relaxed);
  font-size: var(--font-size-base);
}

.chapter-body ul,
.chapter-body ol {
  margin: var(--spacing-md) 0;
  padding-left: var(--spacing-xl);
  font-family: var(--font-family-serif);
}

.chapter-body li {
  margin-bottom: var(--spacing-sm);
  line-height: var(--line-height-relaxed);
  font-size: var(--font-size-base);
}

/* ========================================
   引用块样式 - Requirements: 8.1, 8.2, 8.3
   ======================================== */

.chapter-blockquote {
  margin: var(--spacing-lg) 0;
  padding: var(--spacing-md) var(--spacing-lg);
  border-left: 4px solid var(--color-accent);
  background-color: var(--color-paper-aged);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  font-family: var(--font-family-serif);
  font-style: italic;
}

.blockquote-text {
  font-family: var(--font-family-serif);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  margin-bottom: var(--spacing-sm);
  text-indent: 0;
  color: var(--color-ink-muted);
  line-height: var(--line-height-relaxed);
}

.blockquote-source {
  display: block;
  font-family: var(--font-family-serif);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-normal);
  color: var(--color-ink-faded);
  text-align: right;
  font-style: normal;
  line-height: var(--line-height-normal);
}

.chapter-body blockquote {
  margin: var(--spacing-lg) 0;
  padding: var(--spacing-md) var(--spacing-lg);
  border-left: 4px solid var(--color-accent);
  background-color: var(--color-paper-aged);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  font-family: var(--font-family-serif);
  font-style: italic;
  font-size: var(--font-size-base);
  color: var(--color-ink-muted);
  line-height: var(--line-height-relaxed);
}

.chapter-body blockquote p {
  text-indent: 0;
  margin-bottom: var(--spacing-sm);
}

.chapter-body blockquote p:last-child {
  margin-bottom: 0;
}

/* ========================================
   表格样式 - Requirements: 8.1, 8.2, 8.3
   ======================================== */

.chapter-body table {
  width: 100%;
  margin: var(--spacing-lg) 0;
  border-collapse: collapse;
  font-family: var(--font-family-serif);
  font-size: var(--font-size-sm);
  line-height: var(--line-height-normal);
}

.chapter-body th,
.chapter-body td {
  padding: var(--spacing-sm) var(--spacing-md);
  border: 1px solid var(--border-color-light);
  text-align: left;
  font-family: var(--font-family-serif);
}

.chapter-body th {
  background-color: var(--color-paper-dark);
  font-weight: var(--font-weight-semibold);
  color: var(--color-ink);
}

.chapter-body tr:nth-child(even) {
  background-color: var(--color-paper-light);
}

/* ========================================
   分隔线样式 - Requirements: 8.1, 8.4
   ======================================== */

.chapter-body hr {
  border: none;
  border-top: 1px solid var(--border-color-light);
  margin: var(--spacing-xl) 0;
  position: relative;
}

.chapter-body hr::after {
  content: '§';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background-color: var(--color-paper);
  padding: 0 var(--spacing-md);
  color: var(--color-ink-faded);
  font-family: var(--font-family-serif);
  font-size: var(--font-size-lg);
  line-height: 1;
}


/* ========================================
   交互演示样式
   Requirements: 4.7 - 交互式Canvas演示
   ======================================== */

.interactive-demo {
  background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
  border-radius: 12px;
  padding: 20px;
  margin: 24px 0;
  box-shadow: 0 4px 20px rgba(0,0,0,0.3);
}

.interactive-demo canvas {
  display: block;
  margin: 0 auto;
  background: #0f0f1a;
  border-radius: 8px;
  max-width: 100%;
  height: auto;
}

.demo-controls {
  margin-top: 15px;
  color: #e0e0e0;
  font-size: 14px;
}

.demo-controls .control-group {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
  flex-wrap: wrap;
}

.demo-controls .control-group label {
  min-width: 140px;
  font-family: var(--font-family-sans);
}

.demo-controls input[type="range"] {
  flex: 1;
  max-width: 200px;
  min-width: 100px;
  accent-color: #4ecdc4;
  height: 6px;
  cursor: pointer;
}

.demo-info {
  padding: 12px;
  background: rgba(255,255,255,0.05);
  border-radius: 6px;
  font-family: var(--font-family-mono, monospace);
}

.demo-info .info-row {
  display: flex;
  flex-wrap: wrap;
  gap: 15px;
  margin-bottom: 8px;
}

.demo-info .info-row:last-child {
  margin-bottom: 0;
}

.demo-info span {
  color: #4ecdc4;
}

/* 响应式调整 */
@media (max-width: 768px) {
  .interactive-demo {
    padding: 15px;
    margin: 16px 0;
  }
  
  .demo-controls .control-group {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .demo-controls input[type="range"] {
    width: 100%;
    max-width: none;
  }
  
  .demo-info .info-row {
    flex-direction: column;
    gap: 8px;
  }
}


/* 光照模型按钮样式 */
.model-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 12px;
}

.lighting-model-btn {
  padding: 8px 16px;
  border: 1px solid #4ecdc4;
  background: transparent;
  color: #4ecdc4;
  border-radius: 20px;
  cursor: pointer;
  font-size: 13px;
  transition: all 0.2s ease;
}

.lighting-model-btn:hover {
  background: rgba(78, 205, 196, 0.2);
}

.lighting-model-btn.active {
  background: #4ecdc4;
  color: #1a1a2e;
  font-weight: bold;
}

/* 响应式调整 */
@media (max-width: 768px) {
  .model-buttons {
    justify-content: center;
  }
  
  .lighting-model-btn {
    padding: 6px 12px;
    font-size: 12px;
  }
}


/* 凹凸映射按钮样式 */
.button-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 10px;
  flex-wrap: wrap;
}

.button-label {
  color: #aaa;
  font-size: 13px;
  min-width: 50px;
}

.bump-mode-btn,
.bump-pattern-btn {
  padding: 6px 14px;
  border: 1px solid #4ecdc4;
  background: transparent;
  color: #4ecdc4;
  border-radius: 16px;
  cursor: pointer;
  font-size: 12px;
  transition: all 0.2s ease;
}

.bump-mode-btn:hover,
.bump-pattern-btn:hover {
  background: rgba(78, 205, 196, 0.2);
}

.bump-mode-btn.active,
.bump-pattern-btn.active {
  background: #4ecdc4;
  color: #1a1a2e;
  font-weight: bold;
}


/* 素描对比演示样式 */
.sketch-compare {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin-bottom: 15px;
  flex-wrap: wrap;
}

.sketch-compare canvas {
  border-radius: 8px;
  box-shadow: 0 2px 10px rgba(0,0,0,0.3);
}

@media (max-width: 768px) {
  .sketch-compare {
    gap: 10px;
  }
  
  .sketch-compare canvas {
    width: 120px;
    height: 120px;
  }
}


/* 模糊对比演示样式 */
.blur-compare {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin-bottom: 15px;
  flex-wrap: wrap;
}

.blur-compare canvas {
  border-radius: 8px;
  box-shadow: 0 2px 10px rgba(0,0,0,0.3);
}

.blur-type-btn {
  padding: 6px 14px;
  border: 1px solid #4ecdc4;
  background: transparent;
  color: #4ecdc4;
  border-radius: 16px;
  cursor: pointer;
  font-size: 12px;
  transition: all 0.2s ease;
}

.blur-type-btn:hover {
  background: rgba(78, 205, 196, 0.2);
}

.blur-type-btn.active {
  background: #4ecdc4;
  color: #1a1a2e;
  font-weight: bold;
}

@media (max-width: 768px) {
  .blur-compare {
    gap: 10px;
  }
  
  .blur-compare canvas {
    width: 140px;
    height: 140px;
  }
}


/* 折射演示样式 */
.refract-preset-btn {
  padding: 6px 14px;
  border: 1px solid #4ecdc4;
  background: transparent;
  color: #4ecdc4;
  border-radius: 16px;
  cursor: pointer;
  font-size: 12px;
  transition: all 0.2s ease;
}

.refract-preset-btn:hover {
  background: rgba(78, 205, 196, 0.2);
}

.refract-preset-btn.active {
  background: #4ecdc4;
  color: #1a1a2e;
  font-weight: bold;
}


/* 剑特效演示样式 */
.sword-color-btn {
  width: 32px;
  height: 32px;
  border: 2px solid transparent;
  border-radius: 50%;
  cursor: pointer;
  font-size: 12px;
  color: #fff;
  text-shadow: 0 1px 2px rgba(0,0,0,0.5);
  transition: all 0.2s ease;
}

.sword-color-btn:hover {
  transform: scale(1.1);
  box-shadow: 0 0 10px currentColor;
}

.sword-color-btn.active {
  border-color: #fff;
  box-shadow: 0 0 15px currentColor;
}

.toggle-label {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  cursor: pointer;
  padding: 6px 12px;
  border: 1px solid #4ecdc4;
  border-radius: 16px;
  color: #4ecdc4;
  font-size: 13px;
  transition: all 0.2s ease;
}

.toggle-label:hover {
  background: rgba(78, 205, 196, 0.2);
}

.toggle-label input[type="checkbox"] {
  accent-color: #4ecdc4;
  width: 16px;
  height: 16px;
  cursor: pointer;
}

.toggle-label input[type="checkbox"]:checked + span {
  color: #4ecdc4;
}


/* MVP矩阵演示样式 */
.mvp-btn {
  padding: 6px 14px;
  border: 1px solid #4ecdc4;
  background: transparent;
  color: #4ecdc4;
  border-radius: 16px;
  cursor: pointer;
  font-size: 12px;
  transition: all 0.2s ease;
}

.mvp-btn:hover {
  background: rgba(78, 205, 196, 0.2);
}

.mvp-btn-primary {
  background: #4ecdc4;
  color: #1a1a2e;
  font-weight: bold;
}

.mvp-btn-primary:hover {
  background: #3dbdb5;
}

.matrix-editor {
  margin-top: 15px;
  padding: 12px;
  background: rgba(255, 255, 255, 0.05);
  border-radius: 8px;
}

.matrix-label {
  color: #aaa;
  font-size: 13px;
  margin-bottom: 10px;
}

.matrix-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 6px;
  margin-bottom: 12px;
}

.matrix-input {
  width: 100%;
  padding: 8px;
  background: rgba(0, 0, 0, 0.3);
  border: 1px solid #4ecdc4;
  border-radius: 4px;
  color: #4ecdc4;
  font-family: var(--font-family-mono, monospace);
  font-size: 13px;
  text-align: center;
  box-sizing: border-box;
}

.matrix-input:focus {
  outline: none;
  border-color: #fff;
  background: rgba(78, 205, 196, 0.1);
}

@media (max-width: 768px) {
  .matrix-grid {
    gap: 4px;
  }
  
  .matrix-input {
    padding: 6px 4px;
    font-size: 11px;
  }
}


/* 噪声演示样式 */
.noise-type-btn {
  padding: 5px 10px;
  border: 1px solid #4ecdc4;
  background: transparent;
  color: #4ecdc4;
  border-radius: 14px;
  cursor: pointer;
  font-size: 11px;
  transition: all 0.2s ease;
}

.noise-type-btn:hover {
  background: rgba(78, 205, 196, 0.2);
}

.noise-type-btn.active {
  background: #4ecdc4;
  color: #1a1a2e;
  font-weight: bold;
}

@media (max-width: 768px) {
  .noise-type-btn {
    padding: 4px 8px;
    font-size: 10px;
  }
}


/* 答案展开样式 */
.answer-reveal {
  margin-top: 1rem;
  border: 1px solid var(--color-ink-light);
  border-radius: 8px;
  overflow: hidden;
}

.answer-reveal summary {
  padding: 0.75rem 1rem;
  background: var(--color-paper-dark);
  cursor: pointer;
  font-weight: 600;
  color: var(--color-accent);
  user-select: none;
}

.answer-reveal summary:hover {
  background: var(--color-ink-light);
}

.answer-reveal[open] summary {
  border-bottom: 1px solid var(--color-ink-light);
}

.answer-content {
  padding: 1rem;
  background: var(--color-paper);
}

.answer-content pre {
  background: #2d2d2d;
  padding: 1rem;
  border-radius: 4px;
  overflow-x: auto;
  font-size: 0.9em;
}

.answer-content pre code {
  color: #f8f8f2;
}

.answer-content ol {
  padding-left: 1.5rem;
}

.answer-content li {
  margin-bottom: 0.5rem;
}