/* 第一篇章：绿皮记忆·经济起步的负重前行 */

/* 基础设置 */
.ch-1 {
  position: relative;
  width: 100%;
  height: 100%;
  overflow: hidden;
  background-color: #2c1810; /* 深棕色作为备用背景 */
}

/* 横向长图背景 */
.chapter-bg {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%; /* 6页的宽度 */
  height: 100%;
  background-image: url('../img/s1/bg.PNG');
  background-size: cover;
  background-repeat: no-repeat;
  background-position: 0% 50%;
  z-index: 1;
  transition: transform 1s cubic-bezier(0.4, 0, 0.2, 1);
  filter: brightness(0.9) contrast(1.1);
}

/* 固定绿皮火车 */
.train-left {
  position: absolute;
  bottom: 12%;
  left: 5%;
  width: 40%;
  height: 25%;
  min-width: 400px;
  min-height: 200px;
  background-image: url('../img/s1/bf-grenn-train.PNG');
  background-size: contain;
  background-repeat: no-repeat;
  background-position: left bottom;
  z-index: 2;
  pointer-events: none;
  filter: 
    drop-shadow(5px 5px 10px rgba(0, 0, 0, 0.5))
    drop-shadow(0 0 20px rgba(139, 69, 19, 0.3));
  animation: trainFloat 6s ease-in-out infinite;
  transform-origin: bottom left;
}

/* 火车浮动动画 */
@keyframes trainFloat {
  0%, 100% { 
    transform: translateY(0) rotate(0.5deg); 
  }
  25% { 
    transform: translateY(-8px) rotate(-0.3deg); 
  }
  50% { 
    transform: translateY(-12px) rotate(0.8deg); 
  }
  75% { 
    transform: translateY(-5px) rotate(-0.5deg); 
  }
}

/* 章节标题 */
.chapter-header {
  position: absolute;
  top: 5%;
  left: 0;
  width: 100%;
  text-align: center;
  z-index: 10;
  padding: 20px;
  animation: headerSlideIn 1s cubic-bezier(0.4, 0, 0.2, 1) forwards;
  opacity: 0;
  transform: translateY(-30px);
}

@keyframes headerSlideIn {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.chapter-number {
  font-family: 'zhengwen', serif;
  font-size: 1.3rem;
  color: #FFD700;
  text-shadow: 
    2px 2px 4px rgba(0, 0, 0, 0.8),
    0 0 10px rgba(255, 215, 0, 0.5);
  margin-bottom: 8px;
  letter-spacing: 3px;
  font-weight: 500;
}

.chapter-title {
  font-family: 'zhengwen', serif;
  font-size: 2rem;
  color: #FFFFFF;
  text-shadow: 
    3px 3px 6px rgba(0, 0, 0, 0.9),
    0 0 25px rgba(255, 215, 0, 0.7),
    0 0 50px rgba(255, 215, 0, 0.3);
  padding: 15px 40px;
  background: linear-gradient(135deg, 
    rgba(139, 69, 19, 0.85) 0%,
    rgba(160, 82, 45, 0.9) 50%,
    rgba(139, 69, 19, 0.85) 100%);
  border-radius: 15px;
  display: inline-block;
  backdrop-filter: blur(12px);
  border: 3px solid rgba(210, 105, 30, 0.8);
  box-shadow: 
    0 15px 35px rgba(0, 0, 0, 0.5),
    inset 0 0 50px rgba(255, 215, 0, 0.2);
  position: relative;
  overflow: hidden;
}

.chapter-title::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: linear-gradient(
    45deg,
    transparent 30%,
    rgba(255, 215, 0, 0.1) 50%,
    transparent 70%
  );
  animation: titleShine 3s linear infinite;
}

@keyframes titleShine {
  to {
    transform: translateX(100%) translateY(100%);
  }
}

/* 连续内容容器 */
.chapter-content {
  position: absolute;
  top: 20%;
  left: 0;
  width: 600%; /* 6个内容部分 */
  height: 65%;
  display: flex;
  z-index: 5;
  transition: transform 1s cubic-bezier(0.4, 0, 0.2, 1);
  will-change: transform;
}

.content-section {
  width: 16.6667%; /* 100% / 6 */
  height: 100%;
  padding: 20px 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.content-section.active {
  opacity: 1;
  transform: translateY(0);
}

/* 内容盒子 */
.content-box {
  background: linear-gradient(135deg,
    rgba(255, 253, 250, 0.95) 0%,
    rgba(255, 248, 240, 0.97) 50%,
    rgba(255, 245, 235, 0.95) 100%);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-radius: 20px;
  padding: 35px;
  max-width: 550px;
  width: 90%;
  box-shadow: 
    0 20px 50px rgba(0, 0, 0, 0.4),
    0 0 60px rgba(255, 217, 102, 0.5) inset,
    0 5px 15px rgba(139, 69, 19, 0.2);
  border: 3px solid #D2691E;
  position: relative;
  overflow: hidden;
  animation: boxFloatIn 0.8s cubic-bezier(0.4, 0, 0.2, 1) forwards;
  transform-origin: center;
}

.content-box::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, 
    #8B4513 0%,
    #D2691E 50%,
    #8B4513 100%);
  border-radius: 20px 20px 0 0;
}

.content-box::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, 
    #8B4513 0%,
    #D2691E 50%,
    #8B4513 100%);
  border-radius: 0 0 20px 20px;
}

@keyframes boxFloatIn {
  0% {
    opacity: 0;
    transform: translateY(30px) scale(0.95);
  }
  100% {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

/* 标题样式 */
.content-box h2 {
  font-family: 'zhengwen', serif;
  color: #8B4513;
  font-size: 1.8rem;
  margin-bottom: 25px;
  text-align: center;
  padding-bottom: 15px;
  border-bottom: 3px solid #D2691E;
  text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.1);
  position: relative;
}

.content-box h2::after {
  content: '';
  position: absolute;
  bottom: -3px;
  left: 25%;
  width: 50%;
  height: 3px;
  background: linear-gradient(90deg, 
    transparent 0%,
    #FFD700 50%,
    transparent 100%);
}

.content-box h3 {
  font-family: 'zhengwen', serif;
  color: #8B4513;
  font-size: 1.5rem;
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.content-box h3 i {
  color: #D2691E;
  font-size: 1.3rem;
}

.content-box h4 {
  font-family: 'zhengwen', serif;
  color: #5D4037;
  font-size: 1.3rem;
  margin-bottom: 15px;
}

/* 段落样式 */
.content-box p {
  color: #5D4037;
  font-size: 1.1rem;
  line-height: 1.7;
  margin-bottom: 18px;
  text-align: justify;
}

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

/* 内容图片 */
.content-image {
  margin: 25px 0;
  border-radius: 12px;
  overflow: hidden;
  border: 2px solid #D2691E;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
}

.image-placeholder {
  background: linear-gradient(135deg, #A0522D, #8B4513);
  padding: 40px 20px;
  text-align: center;
  color: #FFE8A1;
}

.image-placeholder i {
  font-size: 3rem;
  margin-bottom: 15px;
  opacity: 0.9;
}

.image-placeholder p {
  color: #FFE8A1;
  font-size: 1rem;
  margin: 0;
  opacity: 0.9;
}

/* 高亮卡片 */
.highlight-card {
  background: linear-gradient(135deg, #FFF8E1, #FFECB3);
  border-radius: 15px;
  padding: 25px;
  margin: 20px 0;
  border-left: 6px solid #D2691E;
  box-shadow: 0 10px 25px rgba(139, 69, 19, 0.15);
  position: relative;
  overflow: hidden;
}

.highlight-card::before {
  content: '';
  position: absolute;
  top: -10px;
  right: -10px;
  width: 40px;
  height: 40px;
  background: rgba(210, 105, 30, 0.1);
  border-radius: 50%;
}

.card-header {
  display: flex;
  align-items: center;
  gap: 15px;
  margin-bottom: 15px;
}

.card-header i {
  font-size: 1.8rem;
  color: #8B4513;
}

.card-body p {
  margin-bottom: 20px;
}

/* 事实卡片 */
.fact-card {
  background: white;
  border-radius: 12px;
  padding: 20px;
  margin: 20px 0;
  border: 2px solid #D2691E;
  display: flex;
  gap: 20px;
  align-items: flex-start;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
  transition: transform 0.3s ease;
}

.fact-card:hover {
  transform: translateY(-5px);
}

.fact-icon {
  flex-shrink: 0;
  width: 50px;
  height: 50px;
  background: linear-gradient(135deg, #8B4513, #D2691E);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 1.5rem;
}

.fact-content h4 {
  margin-bottom: 10px;
}

/* 统计数据容器 */
.stats-container {
  margin: 30px 0;
}

.stat-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 25px;
}

.stat-item {
  background: linear-gradient(135deg, #8B4513, #A0522D);
  color: #FFE8A1;
  padding: 25px;
  border-radius: 15px;
  text-align: center;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
}

.stat-item::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, #FFD700, #FFA500);
}

.stat-item:hover {
  transform: translateY(-8px);
  box-shadow: 0 15px 35px rgba(0, 0, 0, 0.4);
}

.stat-value {
  font-family: 'zhengwen', serif;
  font-size: 2rem;
  font-weight: bold;
  margin-bottom: 10px;
  text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.3);
}

.stat-label {
  font-size: 1.05rem;
  margin-bottom: 8px;
  opacity: 0.95;
  font-weight: 500;
}

.stat-note {
  font-size: 0.9rem;
  opacity: 0.8;
  font-style: italic;
}

/* 参考卡片 */
.reference-card {
  background: rgba(255, 248, 225, 0.9);
  border-radius: 12px;
  padding: 20px;
  margin: 25px 0;
  border: 2px solid #8B4513;
}

.ref-header {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 15px;
  padding-bottom: 10px;
  border-bottom: 2px solid #D2691E;
}

.ref-header i {
  color: #8B4513;
  font-size: 1.2rem;
}

.ref-header span {
  font-family: 'zhengwen', serif;
  color: #8B4513;
  font-size: 1.2rem;
  font-weight: bold;
}

.ref-content p {
  margin-bottom: 15px;
}

.ref-links {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.ref-link {
  display: flex;
  align-items: center;
  gap: 10px;
  color: #8B4513;
  text-decoration: none;
  padding: 10px 15px;
  background: rgba(255, 255, 255, 0.8);
  border-radius: 8px;
  transition: all 0.3s ease;
  border: 1px solid rgba(210, 105, 30, 0.3);
}

.ref-link:hover {
  background: white;
  transform: translateX(5px);
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

/* 双卡片容器 */
.dual-card-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 30px;
  margin: 30px 0;
}

.dual-card {
  background: white;
  border-radius: 15px;
  padding: 25px;
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.1);
  border: 2px solid #D2691E;
  transition: all 0.3s ease;
  display: flex;
  flex-direction: column;
  height: 100%;
}

.dual-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 18px 40px rgba(0, 0, 0, 0.15);
}

.card-title {
  display: flex;
  align-items: center;
  gap: 15px;
  margin-bottom: 20px;
  padding-bottom: 15px;
  border-bottom: 2px solid rgba(210, 105, 30, 0.3);
}

.title-icon {
  width: 50px;
  height: 50px;
  background: linear-gradient(135deg, #8B4513, #D2691E);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 1.5rem;
}

.card-text {
  flex-grow: 1;
  margin-bottom: 20px;
}

.card-text p {
  margin-bottom: 15px;
}

.card-footer {
  margin-top: auto;
}

.card-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: #8B4513;
  text-decoration: none;
  font-weight: 500;
  padding: 8px 16px;
  background: rgba(255, 248, 225, 0.8);
  border-radius: 6px;
  transition: all 0.3s ease;
}

.card-link:hover {
  background: #FFE8A1;
  transform: translateX(3px);
}

/* 媒体链接 */
.media-link {
  margin: 25px 0;
  text-align: center;
}

.video-btn {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  background: linear-gradient(135deg, #D2691E, #8B4513);
  color: white;
  padding: 14px 30px;
  border-radius: 8px;
  text-decoration: none;
  font-weight: bold;
  border: none;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 8px 20px rgba(139, 69, 19, 0.3);
  font-size: 1.05rem;
}

.video-btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 12px 25px rgba(139, 69, 19, 0.4);
}

.video-btn:active {
  transform: translateY(-1px);
}

.link-source {
  display: block;
  margin-top: 8px;
  font-size: 0.9rem;
  color: #795548;
  opacity: 0.8;
}

/* 问答部分 */
.quiz-section {
  width: 100%;
}

.quiz-header {
  display: flex;
  align-items: center;
  gap: 15px;
  margin-bottom: 25px;
  padding-bottom: 15px;
  border-bottom: 2px solid #D2691E;
}

.quiz-header i {
  font-size: 2rem;
  color: #8B4513;
}

.quiz-question {
  font-family: 'zhengwen', serif;
  font-size: 1.4rem;
  color: #8B4513;
  text-align: center;
  margin-bottom: 30px;
  padding: 15px;
  background: linear-gradient(135deg, rgba(255, 248, 225, 0.8), rgba(255, 236, 179, 0.8));
  border-radius: 10px;
  border-left: 4px solid #8B4513;
}

.quiz-options {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 15px;
  margin-bottom: 25px;
}

.quiz-option {
  background: white;
  border: 3px solid #D2691E;
  border-radius: 10px;
  padding: 18px 20px;
  display: flex;
  align-items: center;
  gap: 15px;
  cursor: pointer;
  transition: all 0.3s ease;
  font-size: 1.1rem;
  text-align: left;
}

.quiz-option:hover {
  background: #FFE8A1;
  transform: translateY(-3px);
  box-shadow: 0 8px 20px rgba(139, 69, 19, 0.2);
}

.quiz-option.correct {
  background: linear-gradient(135deg, #4CAF50, #388E3C);
  color: white;
  border-color: #2E7D32;
}

.quiz-option.incorrect {
  background: linear-gradient(135deg, #F44336, #D32F2F);
  color: white;
  border-color: #C62828;
}

.option-letter {
  width: 30px;
  height: 30px;
  background: #8B4513;
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  flex-shrink: 0;
}

.quiz-option.correct .option-letter,
.quiz-option.incorrect .option-letter {
  background: white;
  color: inherit;
}

.quiz-feedback {
  padding: 20px;
  background: linear-gradient(135deg, #FFF8E1, #FFECB3);
  border-radius: 12px;
  margin-top: 20px;
  border-left: 5px solid #8B4513;
  display: none;
  animation: fadeIn 0.5s ease;
}

.quiz-feedback.show {
  display: block;
}

.feedback-header {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 15px;
  padding-bottom: 10px;
  border-bottom: 2px solid rgba(139, 69, 19, 0.3);
}

.feedback-header i {
  color: #8B4513;
  font-size: 1.5rem;
}

.feedback-content p {
  margin-bottom: 10px;
}

.feedback-content strong {
  color: #8B4513;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* 结语部分 */
.conclusion-section {
  text-align: center;
  margin-bottom: 40px;
}

.conclusion-header {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  margin-bottom: 30px;
}

.conclusion-header i {
  font-size: 2rem;
  color: #8B4513;
  opacity: 0.7;
}

.conclusion-content {
  background: linear-gradient(135deg, 
    rgba(139, 69, 19, 0.95), 
    rgba(160, 82, 45, 0.95));
  color: #FFE8A1;
  padding: 35px;
  border-radius: 20px;
  box-shadow: 
    0 15px 40px rgba(0, 0, 0, 0.4),
    inset 0 0 50px rgba(255, 215, 0, 0.1);
  border: 2px solid rgba(255, 215, 0, 0.3);
}

.conclusion-content p {
  color: #FFE8A1;
  font-size: 1.2rem;
  line-height: 1.8;
  margin-bottom: 20px;
  font-style: italic;
  text-align: justify;
}

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

/* 下一章提示 */
.next-chapter-prompt {
  text-align: center;
  padding: 30px;
  background: linear-gradient(135deg,
    rgba(255, 255, 255, 0.95),
    rgba(255, 248, 240, 0.98));
  border-radius: 20px;
  border: 3px dashed #D2691E;
  position: relative;
  overflow: hidden;
}

.prompt-animation {
  margin-bottom: 25px;
}

.arrow-container {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  animation: arrowPulse 2s ease-in-out infinite;
}

.arrow-line {
  width: 100px;
  height: 3px;
  background: linear-gradient(90deg, #8B4513, #D2691E, #8B4513);
  position: relative;
}

.arrow-line::before {
  content: '';
  position: absolute;
  top: -3px;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, #FFD700, transparent);
  animation: lineShine 2s linear infinite;
}

@keyframes arrowPulse {
  0%, 100% { transform: scale(1); opacity: 1; }
  50% { transform: scale(1.05); opacity: 0.8; }
}

@keyframes lineShine {
  0% { transform: translateX(-100%); }
  100% { transform: translateX(100%); }
}

.arrow-container i {
  font-size: 2rem;
  color: #8B4513;
}

.prompt-content h3 {
  font-family: 'zhengwen', serif;
  color: #8B4513;
  font-size: 1.8rem;
  margin-bottom: 10px;
}

.prompt-main {
  font-size: 1.3rem;
  color: #5D4037;
  margin-bottom: 5px;
  font-weight: bold;
}

.prompt-sub {
  font-size: 1.1rem;
  color: #795548;
  margin-bottom: 25px;
  opacity: 0.9;
}

.prompt-actions {
  display: flex;
  justify-content: center;
  gap: 20px;
  flex-wrap: wrap;
}

.next-chapter-btn {
  background: linear-gradient(135deg, #8B4513, #D2691E);
  color: white;
  border: none;
  padding: 15px 40px;
  font-size: 1.2rem;
  font-family: 'zhengwen', serif;
  border-radius: 50px;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 
    0 10px 30px rgba(139, 69, 19, 0.4),
    0 0 30px rgba(255, 215, 0, 0.2) inset;
  display: flex;
  align-items: center;
  gap: 12px;
}

.next-chapter-btn:hover {
  transform: translateY(-5px);
  box-shadow: 
    0 15px 35px rgba(139, 69, 19, 0.6),
    0 0 40px rgba(255, 215, 0, 0.3) inset;
}

.restart-chapter-btn {
  background: white;
  color: #8B4513;
  border: 2px solid #D2691E;
  padding: 15px 30px;
  font-size: 1rem;
  border-radius: 50px;
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  gap: 10px;
}

.restart-chapter-btn:hover {
  background: #FFE8A1;
  transform: translateY(-3px);
  box-shadow: 0 8px 20px rgba(139, 69, 19, 0.2);
}

/* 章节指示器 */
.chapter-indicator {
  position: absolute;
  bottom: 5%;
  left: 0;
  width: 100%;
  text-align: center;
  z-index: 10;
  padding: 20px;
  pointer-events: none;
}

.indicator-dots {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin-bottom: 15px;
  pointer-events: auto;
}

.dot {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.3);
  cursor: pointer;
  transition: all 0.3s ease;
  border: 2px solid transparent;
  position: relative;
}

.dot:hover {
  background: rgba(255, 255, 255, 0.5);
  transform: scale(1.2);
}

.dot.active {
  background: #FFD700;
  transform: scale(1.4);
  box-shadow: 
    0 0 15px #FFD700,
    0 0 30px rgba(255, 215, 0, 0.5);
  border-color: #FFA500;
}

.dot.active::after {
  content: '';
  position: absolute;
  top: -4px;
  left: -4px;
  right: -4px;
  bottom: -4px;
  border: 2px solid rgba(255, 215, 0, 0.3);
  border-radius: 50%;
  animation: dotPulse 2s infinite;
}

@keyframes dotPulse {
  0%, 100% { transform: scale(1); opacity: 1; }
  50% { transform: scale(1.2); opacity: 0.5; }
}

.indicator-text {
  color: rgba(255, 255, 255, 0.9);
  font-size: 1rem;
  font-family: 'PingFang', sans-serif;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 15px;
}

.indicator-text i {
  font-size: 1.2rem;
  animation: pulse 2s infinite;
}

.indicator-text span {
  min-width: 150px;
  text-align: center;
}

@keyframes pulse {
  0%, 100% { opacity: 0.7; }
  50% { opacity: 1; }
}

/* 章节导航按钮 */
.chapter-navigation {
  position: absolute;
  top: 50%;
  left: 0;
  width: 100%;
  transform: translateY(-50%);
  display: flex;
  justify-content: space-between;
  padding: 0 20px;
  z-index: 8;
  pointer-events: none;
}

.nav-btn {
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background: rgba(139, 69, 19, 0.8);
  backdrop-filter: blur(10px);
  border: 2px solid rgba(255, 215, 0, 0.5);
  color: #FFD700;
  font-size: 1.5rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s ease;
  pointer-events: auto;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
}

.nav-btn:hover {
  background: rgba(160, 82, 45, 0.9);
  transform: scale(1.1);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.4);
}

.nav-btn:active {
  transform: scale(0.95);
}

/* 响应式设计 */
@media screen and (max-width: 1400px) {
  .chapter-title {
    font-size: 1.8rem;
    padding: 12px 30px;
  }
  
  .content-box {
    max-width: 500px;
    padding: 30px;
  }
  
  .content-box h2 {
    font-size: 1.6rem;
  }
  
  .dual-card-container {
    grid-template-columns: 1fr;
    gap: 25px;
  }
  
  .train-left {
    width: 45%;
    min-width: 350px;
  }
}

@media screen and (max-width: 992px) {
  .chapter-title {
    font-size: 1.6rem;
    padding: 10px 25px;
  }
  
  .chapter-number {
    font-size: 1.2rem;
  }
  
  .content-section {
    padding: 20px 30px;
  }
  
  .content-box {
    padding: 25px;
    width: 95%;
  }
  
  .content-box h2 {
    font-size: 1.4rem;
    margin-bottom: 20px;
  }
  
  .content-box h3 {
    font-size: 1.3rem;
  }
  
  .content-box p {
    font-size: 1.05rem;
  }
  
  .quiz-options {
    grid-template-columns: 1fr;
  }
  
  .train-left {
    width: 50%;
    min-width: 300px;
    bottom: 15%;
  }
  
  .prompt-actions {
    flex-direction: column;
    align-items: center;
  }
  
  .next-chapter-btn,
  .restart-chapter-btn {
    width: 100%;
    max-width: 300px;
    justify-content: center;
  }
}

@media screen and (max-width: 768px) {
  .chapter-header {
    top: 3%;
    padding: 15px;
  }
  
  .chapter-title {
    font-size: 1.4rem;
    padding: 8px 20px;
  }
  
  .chapter-content {
    top: 15%;
    height: 70%;
  }
  
  .content-section {
    padding: 15px 20px;
  }
  
  .content-box {
    padding: 20px;
  }
  
  .content-box h2 {
    font-size: 1.3rem;
  }
  
  .content-box h3 {
    font-size: 1.2rem;
  }
  
  .content-box p {
    font-size: 1rem;
    line-height: 1.6;
  }
  
  .train-left {
    width: 60%;
    min-width: 250px;
    bottom: 18%;
  }
  
  .stat-row {
    grid-template-columns: 1fr;
    gap: 20px;
  }
  
  .stat-value {
    font-size: 1.8rem;
  }
  
  .nav-btn {
    width: 45px;
    height: 45px;
    font-size: 1.3rem;
  }
  
  .indicator-dots {
    gap: 15px;
  }
  
  .dot {
    width: 12px;
    height: 12px;
  }
  
  .indicator-text {
    font-size: 0.9rem;
  }
}



/* 打印样式 */
@media print {
  .ch-1 {
    background: white !important;
    color: black !important;
  }
  
  .chapter-bg,
  .train-left,
  .nav-btn,
  .chapter-indicator {
    display: none !important;
  }
  
  .content-box {
    box-shadow: none !important;
    border: 1px solid #ccc !important;
  }
}