/* ==================== 全局样式 ==================== */
html {
  overflow-y: scroll;
}

body {
  background: #f8f9fa;
  font-family: "Microsoft YaHei", -apple-system, sans-serif;
  padding: 30px 15px;
}

/* ==================== 欢迎页面样式 ==================== */
.welcome-page {
  text-align: center;
  padding: 60px 20px;
}

.welcome-page .avatar {
  width: 120px;
  height: 120px;
  border-radius: 16px;
  margin: 0 auto 30px;
  border: 4px solid #3498db;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  transition: all 0.3s;
  cursor: pointer;
}

.welcome-page .avatar:hover {
  transform: translateY(-8px);
  box-shadow: 0 12px 24px rgba(52, 152, 219, 0.4);
}

.welcome-page h2 {
  font-size: 32px;
  color: #2c3e50;
  margin-bottom: 15px;
}

.welcome-page .author {
  font-size: 18px;
  color: #7f8c8d;
  margin-bottom: 40px;
}

.welcome-page .author a {
  color: #3498db;
  text-decoration: none;
  font-weight: 700;
  transition: all 0.3s;
  display: inline-block;
  padding: 4px 12px;
  border-radius: 4px;
}

.welcome-page .author a:hover {
  color: #3498db;
  transform: translateY(-3px);
  box-shadow: 0 6px 12px rgba(52, 152, 219, 0.3);
  background: rgba(52, 152, 219, 0.1);
}

.welcome-features {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 30px;
  margin-top: 50px;
  max-width: 900px;
  margin-left: auto;
  margin-right: auto;
}

.feature-card {
  background: white;
  padding: 30px;
  border-radius: 4px;
  border: 2px solid #e1e8ed;
  transition: all 0.2s;
}

.feature-card:hover {
  border-color: #3498db;
  transform: translateY(-5px);
}

.feature-card .icon {
  font-size: 48px;
  margin-bottom: 15px;
}

.feature-card h4 {
  color: #2c3e50;
  margin-bottom: 10px;
}

.feature-card p {
  color: #7f8c8d;
  font-size: 14px;
}

/* ==================== 主标题和导航 ==================== */
.main-title {
  font-size: 36px;
  font-weight: 700;
  color: #2c3e50;
  text-align: center;
  margin-bottom: 40px;
}

.nav-pills .nav-link {
  font-size: 18px;
  font-weight: 600;
  padding: 12px 40px;
  border-radius: 4px;
  color: #5a6c7d;
}

.nav-pills .nav-link.active {
  background-color: #3498db;
}

/* ==================== 手风琴样式（简答题） ==================== */
.accordion-button {
  font-size: 17px;
  font-weight: 600;
  color: #2c3e50;
  background-color: #f5f7fa;
}

.accordion-button:not(.collapsed) {
  background-color: #e3f2fd;
  color: #2c3e50;
}

.accordion-button:focus {
  box-shadow: none;
  border-color: #3498db;
}

.accordion-item {
  border: 2px solid #e1e8ed;
  border-left: 4px solid #3498db;
  margin-bottom: 15px;
  border-radius: 4px;
}

.accordion-body {
  font-size: 16px;
  color: #5a6c7d;
  line-height: 2;
}

/* ==================== 编程题样式 ==================== */
.coding-card {
  border-left: 4px solid #2ecc71;
}

.section-label {
  font-size: 18px;
  font-weight: 600;
  color: #2c3e50;
  margin: 25px 0 15px 0;
}

.target-demo {
  background: #ffffff;
  padding: 25px;
  border: 2px solid #f39c12;
  border-radius: 4px;
  margin: 20px 0;
}

.code-editor-area {
  background: #2c3e50;
  border: 2px solid #34495e;
  border-radius: 4px;
  padding: 15px;
  height: 400px;
}

.code-editor-area textarea {
  width: 100%;
  height: 100%;
  background: transparent;
  color: #ecf0f1;
  border: none;
  font-family: "Consolas", "Monaco", monospace;
  font-size: 14px;
  line-height: 1.8;
  resize: none;
  outline: none;
  white-space: nowrap;
  overflow-x: auto;
}

.code-editor-area textarea::placeholder {
  color: #7f8c8d;
}

.preview-area {
  border: 2px solid #e1e8ed;
  border-radius: 4px;
  height: 400px;
  background: white;
}

.answer-accordion .accordion-item {
  border-left: 4px solid #e67e22;
}

.answer-accordion .accordion-button {
  background-color: #fff9e6;
}

.code-block {
  background: #2c3e50;
  color: #ecf0f1;
  padding: 20px;
  border-radius: 4px;
  font-family: "Consolas", "Monaco", monospace;
  font-size: 14px;
  line-height: 1.8;
  overflow: auto;
  max-height: 400px;
  position: relative;
}

.copy-btn {
  position: absolute;
  top: 10px;
  right: 10px;
  background: #3498db;
  color: white;
  border: none;
  padding: 6px 12px;
  border-radius: 4px;
  cursor: pointer;
  font-size: 12px;
  transition: all 0.2s;
  opacity: 0.8;
}

.copy-btn:hover {
  opacity: 1;
  background: #2980b9;
}

.copy-btn.copied {
  background: #2ecc71;
}

.knowledge-box {
  background: #fff3dc;
  border: 2px solid #f39c12;
  border-radius: 4px;
  padding: 20px;
  height: 400px;
  overflow-y: auto;
}

.knowledge-box h5 {
  color: #e67e22;
  font-weight: 600;
  margin-top: 15px;
}

/* ==================== 选择题样式 ==================== */
.quiz-card {
  background: white;
  border: 2px solid #e1e8ed;
  border-left: 4px solid #9c27b0;
  border-radius: 4px;
  padding: 25px;
  margin-bottom: 20px;
  position: relative;
}

.quiz-number {
  color: #9c27b0;
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 15px;
  padding-right: 100px; /* 为讲解按钮留出空间 */
}

.explain-btn {
  position: absolute;
  top: 20px;
  right: 20px;
  background: #ff9800;
  color: white;
  border: none;
  padding: 8px 16px;
  border-radius: 4px;
  cursor: pointer;
  font-size: 14px;
  font-weight: 600;
  transition: all 0.2s;
  white-space: nowrap; /* 防止按钮文字换行 */
  z-index: 10; /* 确保按钮在最上层 */
}

.explain-btn:hover {
  background: #f57c00;
}

/* 选项容器 - 使用flex布局 */
.options-container {
  display: flex;
  flex-direction: column; /* 改为垂直排列 */
  gap: 10px;
  margin-top: 15px;
}

.option-btn {
  display: inline-block;
  width: 100%; /* 单列布局，每个选项独占一行 */
  text-align: left;
  padding: 15px 20px;
  margin: 0; /* 改为0，由gap控制间距 */
  background: #f5f7fa;
  border: 2px solid #e1e8ed;
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.2s;
  font-size: 16px;
  color: #2c3e50;
  box-sizing: border-box;
}

.option-btn:hover:not(:disabled) {
  background: #e8edf3;
  border-color: #9c27b0;
}

.option-btn.correct {
  background: #e8f5e9 !important;
  border-color: #2ecc71 !important;
  color: #2ecc71 !important;
  font-weight: 600;
  cursor: not-allowed;
}

.option-btn.wrong {
  background: #ffebee !important;
  border-color: #e74c3c !important;
  color: #e74c3c !important;
  cursor: not-allowed;
}

.option-btn:disabled {
  cursor: not-allowed;
  opacity: 0.7;
}

.quiz-result {
  margin-top: 15px;
  padding: 15px;
  border-radius: 4px;
  font-weight: 600;
  display: none;
}

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

.quiz-result.correct {
  background: #e8f5e9;
  color: #2ecc71;
  border-left: 4px solid #2ecc71;
}

.quiz-result.wrong {
  background: #ffebee;
  color: #e74c3c;
  border-left: 4px solid #e74c3c;
}

/* ==================== 选择题答题卡样式 ==================== */
/* 圆形浮动按钮 */
.answer-card-toggle {
  position: fixed;
  right: 30px;
  bottom: 30px;
  width: 60px;
  height: 60px;
  background: #9c27b0;
  border-radius: 50%;
  border: none;
  color: white;
  font-size: 24px;
  cursor: move;
  box-shadow: 0 4px 12px rgba(156, 39, 176, 0.4);
  z-index: 1001;
  transition: all 0.3s;
  display: none; /* 默认隐藏，只在选择题页面显示 */
  align-items: center;
  justify-content: center;
}

.answer-card-toggle:hover {
  transform: scale(1.1);
  box-shadow: 0 6px 16px rgba(156, 39, 176, 0.5);
}

.answer-card-toggle.dragging {
  cursor: grabbing;
  opacity: 0.8;
}

/* 答题卡面板 */
.answer-card-panel {
  position: fixed;
  right: 20px;
  bottom: 100px;
  width: 340px;
  background: white;
  border: 2px solid #e1e8ed;
  border-left: 4px solid #9c27b0;
  border-radius: 4px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  z-index: 1000;
  max-height: calc(100vh - 150px);
  overflow-y: auto;
  opacity: 0;
  transform: translateY(20px);
  visibility: hidden;
  transition: opacity 0.3s ease, transform 0.3s ease, visibility 0.3s;
}

.answer-card-panel.show {
  opacity: 1;
  transform: translateY(0);
  visibility: visible;
}

.answer-card-header {
  background: #f5f7fa;
  color: #2c3e50;
  padding: 15px;
  font-weight: 600;
  text-align: center;
  border-bottom: 2px solid #e1e8ed;
  position: sticky;
  top: 0;
  z-index: 10;
  background: white;
}

.answer-card-stats {
  padding: 15px;
  background: white;
  display: flex;
  justify-content: space-around;
  font-size: 14px;
  border-bottom: 1px solid #f0f0f0;
}

.stat-item {
  text-align: center;
}

.stat-number {
  font-size: 24px;
  font-weight: 700;
  margin-bottom: 5px;
}

.stat-label {
  color: #7f8c8d;
  font-size: 12px;
}

.answer-grid {
  padding: 15px;
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 6px;
}

.answer-item {
  width: 36px;
  height: 36px;
  border: 2px solid #e1e8ed;
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.2s;
  font-weight: 600;
  background: #f5f7fa;
  color: #5a6c7d;
  font-size: 13px;
}

.answer-item:hover {
  border-color: #9c27b0;
  background: #e8edf3;
}

.answer-item.correct {
  background: #e8f5e9;
  color: #2ecc71;
  border-color: #2ecc71;
  font-weight: 700;
}

.answer-item.wrong {
  background: #ffebee;
  color: #e74c3c;
  border-color: #e74c3c;
  font-weight: 700;
}

.answer-item.answered {
  border-color: #3498db;
  background: #e3f2fd;
}

.answer-card-footer {
  padding: 15px;
  border-top: 2px solid #e1e8ed;
  position: sticky;
  bottom: 0;
  background: white;
}

.reset-btn {
  width: 100%;
  padding: 10px;
  background: white;
  color: #5a6c7d;
  border: 2px solid #e1e8ed;
  border-radius: 4px;
  cursor: pointer;
  font-weight: 600;
  transition: all 0.2s;
  font-size: 14px;
}

.reset-btn:hover {
  background: #ffebee;
  border-color: #e74c3c;
  color: #e74c3c;
}

/* ==================== 简答题默写区样式 ==================== */
/* 简答题顶部按钮区 */
.short-answer-header {
  margin-bottom: 20px;
  padding: 15px 20px;
  background: #fff;
  border: 2px solid #e1e8ed;
  border-left: 4px solid #3498db;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
  transition: all 0.3s;
}

.short-answer-header:hover {
  box-shadow: 0 4px 8px rgba(52, 152, 219, 0.15);
  border-left-color: #2980b9;
}

.short-answer-header::before {
  content: "📝 简答题练习区";
  font-size: 16px;
  font-weight: 600;
  color: #2c3e50;
}

.short-answer-header .btn {
  transition: all 0.3s;
}

.short-answer-header .btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 2px 8px rgba(220, 53, 69, 0.3);
}

/* 圆形浮动按钮（简答题） */
.short-answer-card-toggle {
  position: fixed;
  right: 30px;
  bottom: 30px;
  width: 60px;
  height: 60px;
  background: #3498db;
  border-radius: 50%;
  border: none;
  color: white;
  font-size: 24px;
  cursor: move;
  box-shadow: 0 4px 12px rgba(52, 152, 219, 0.4);
  z-index: 1001;
  transition: all 0.3s;
  display: none;
  align-items: center;
  justify-content: center;
}

.short-answer-card-toggle:hover {
  transform: scale(1.1);
  box-shadow: 0 6px 16px rgba(52, 152, 219, 0.5);
}

.short-answer-card-toggle.dragging {
  cursor: grabbing;
  opacity: 0.8;
}

/* 简答题默写区面板 */
.short-answer-card-panel {
  position: fixed;
  right: 20px;
  bottom: 100px;
  width: 400px;
  background: white;
  border: 2px solid #e1e8ed;
  border-left: 4px solid #3498db;
  border-radius: 4px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  z-index: 1000;
  max-height: calc(100vh - 150px);
  overflow-y: auto;
  opacity: 0;
  transform: translateY(20px);
  visibility: hidden;
  transition: opacity 0.3s ease, transform 0.3s ease, visibility 0.3s;
}

.short-answer-card-panel.show {
  opacity: 1;
  transform: translateY(0);
  visibility: visible;
}

.short-answer-list {
  padding: 15px;
  max-height: calc(100vh - 300px);
  overflow-y: auto;
}

.short-answer-item {
  margin-bottom: 20px;
  padding-bottom: 20px;
  border-bottom: 1px solid #e1e8ed;
}

.short-answer-item:last-child {
  border-bottom: none;
}

.short-answer-question {
  font-weight: 600;
  color: #2c3e50;
  margin-bottom: 10px;
  font-size: 14px;
  line-height: 1.6;
}

.short-answer-textarea {
  width: 100%;
  min-height: 80px;
  padding: 10px;
  border: 2px solid #e1e8ed;
  border-radius: 4px;
  font-size: 13px;
  line-height: 1.6;
  resize: vertical;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  transition: border-color 0.3s;
}

.short-answer-textarea:focus {
  outline: none;
  border-color: #3498db;
  box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

.short-answer-textarea::placeholder {
  color: #95a5a6;
}

/* 简答题答题区样式优化 */
.short-answer-write-area {
  margin-bottom: 15px;
}

.short-answer-write-area .short-answer-textarea {
  border: 2px solid #e1e8ed;
  border-radius: 4px;
  padding: 12px;
  font-size: 14px;
  line-height: 1.6;
  transition: border-color 0.3s;
}

.short-answer-write-area .short-answer-textarea:focus {
  border-color: #3498db;
  box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
  outline: none;
}

/* AI评分结果样式 */
.ai-score-result {
  animation: fadeInUp 0.3s ease;
}

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

.ai-score-result ul {
  padding-left: 20px;
  margin-bottom: 0;
}

.ai-score-result ul li {
  margin-bottom: 5px;
}

/* ==================== 熟练度标签样式 ==================== */
.proficiency-tag {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 4px 10px;
  background: #f8f9fa;
  border-radius: 20px;
  font-size: 14px;
  margin-left: 10px;
  transition: all 0.3s;
}

.proficiency-tag:hover {
  background: #e9ecef;
}

.star-rating {
  display: inline-flex;
  gap: 2px;
  cursor: pointer;
  user-select: none;
}

.star {
  font-size: 18px;
  color: #ddd;
  transition: all 0.2s;
  cursor: pointer;
}

.star:hover {
  transform: scale(1.2);
}

.star.filled {
  color: #ffd700;
}

.star.level-1 { color: #e74c3c; } /* 1星-红色 */
.star.level-2 { color: #f39c12; } /* 2星-橙色 */
.star.level-3 { color: #f1c40f; } /* 3星-黄色 */
.star.level-4 { color: #2ecc71; } /* 4星-浅绿 */
.star.level-5 { color: #27ae60; } /* 5星-深绿 */

.proficiency-label {
  font-size: 12px;
  color: #666;
  margin-left: 5px;
}

/* 熟练度统计卡片 */
.proficiency-stats {
  margin-top: 30px;
  padding: 20px;
  background: #fff;
  border: 2px solid #e1e8ed;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
}

.proficiency-stats-header {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 15px;
  color: #2c3e50;
  padding-bottom: 12px;
  border-bottom: 2px solid #3498db;
  display: flex;
  align-items: center;
  gap: 8px;
}

.proficiency-stats-header::before {
  content: '📊';
  font-size: 20px;
}

.proficiency-stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 12px;
}

.proficiency-stats .stat-item {
  background: #f8f9fa;
  padding: 15px 10px;
  border-radius: 6px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  transition: all 0.2s;
  border: 1px solid #e1e8ed;
}

.proficiency-stats .stat-item:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(52, 152, 219, 0.15);
  border-color: #3498db;
}

.proficiency-stats .stat-item .icon {
  font-size: 20px;
  line-height: 1;
}

.proficiency-stats .stat-item .label {
  font-size: 12px;
  font-weight: 500;
  color: #5a6c7d;
}

.proficiency-stats .stat-item .count {
  font-size: 24px;
  font-weight: 700;
  color: #2c3e50;
}

/* ==================== 响应式设计 ==================== */

/* iPad 适配 (768px - 1024px) */
@media (max-width: 1024px) and (min-width: 768px) {
  .container {
    max-width: 95%;
  }

  /* 首页卡片适配 iPad */
  .welcome-features {
    gap: 20px;
  }

  .feature-card {
    flex: 0 1 calc(33.333% - 15px);
  }

  /* 答题卡宽度调整 */
  .answer-card-panel {
    width: 320px;
  }

  /* 编程题代码区适配 */
  .code-editor-area textarea {
    font-size: 13px;
  }

  .preview-area {
    min-height: 300px;
  }
}

/* 手机适配 (< 768px) */
@media (max-width: 767px) {
  /* 容器适配 */
  .container {
    padding: 10px;
  }

  .main-title {
    font-size: 28px;
    margin: 20px 0;
  }

  /* 导航标签适配 */
  .nav-pills {
    flex-wrap: wrap;
    gap: 8px;
  }

  .nav-item {
    margin: 0 !important;
    flex: 1 1 calc(50% - 4px);
    min-width: 140px;
  }

  .nav-link {
    font-size: 14px;
    padding: 10px 15px;
  }

  /* 首页卡片纵向排列 */
  .welcome-features {
    flex-direction: column;
    gap: 20px;
  }

  .feature-card {
    flex: 1 1 100%;
    max-width: 100%;
  }

  .avatar {
    width: 80px;
    height: 80px;
  }

  /* 选择题适配 */
  .quiz-card {
    padding: 15px;
    margin-bottom: 15px;
  }

  .quiz-number {
    font-size: 15px;
    padding-right: 80px;
  }

  .explain-btn {
    padding: 6px 12px;
    font-size: 13px;
  }

  /* 选项改为单列 */
  /* 选项已经是单列布局，无需额外设置 */
  .option-btn {
    font-size: 14px;
    padding: 12px 15px;
  }

  /* 答题卡适配 */
  .answer-card-toggle {
    right: 15px;
    bottom: 15px;
    width: 50px;
    height: 50px;
    font-size: 20px;
  }

  .answer-card-panel {
    width: calc(100vw - 30px);
    right: 15px;
    bottom: 80px;
    max-height: calc(100vh - 120px);
  }

  /* 答题卡网格改为5列 */
  .answer-grid {
    grid-template-columns: repeat(5, 1fr);
    gap: 8px;
    padding: 10px;
  }

  .answer-item {
    width: 100%;
    height: 40px;
    font-size: 14px;
  }

  .answer-card-header {
    padding: 12px;
    font-size: 15px;
  }

  .answer-card-stats {
    padding: 12px 10px;
    gap: 10px;
  }

  .stat-number {
    font-size: 20px;
  }

  .stat-label {
    font-size: 11px;
  }

  /* 简答题适配 */
  .short-answer-header {
    padding: 12px 15px;
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }

  .short-answer-header::before {
    font-size: 14px;
  }

  .short-answer-header .btn {
    width: 100%;
  }

  .accordion-button {
    font-size: 14px;
    padding: 12px;
  }

  .accordion-body {
    padding: 15px;
  }

  .short-answer-textarea {
    font-size: 14px;
    min-height: 120px;
  }

  /* 熟练度统计适配 */
  .proficiency-stats {
    padding: 20px 15px;
  }

  .proficiency-stats-header {
    font-size: 16px;
  }

  .proficiency-stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .proficiency-stats .stat-item {
    padding: 12px;
  }

  .proficiency-stats .stat-item .count {
    font-size: 24px;
  }

  /* 编程题适配 - 改为上下堆叠 */
  .row {
    flex-direction: column;
  }

  .col-md-6,
  .col-md-12 {
    width: 100% !important;
    max-width: 100%;
    padding: 0;
  }

  .code-editor-area textarea {
    height: 250px;
    font-size: 13px;
  }

  .preview-area {
    min-height: 250px;
    margin-top: 15px;
  }

  .section-label {
    font-size: 16px;
    margin-top: 20px;
  }

  /* 代码块适配 */
  pre {
    font-size: 12px;
    padding: 12px;
    overflow-x: auto;
  }
}

/* 超小屏幕适配 (< 480px) */
@media (max-width: 479px) {
  .main-title {
    font-size: 24px;
  }

  .nav-link {
    font-size: 13px;
    padding: 8px 10px;
  }

  /* 答题卡网格改为4列 */
  .answer-grid {
    grid-template-columns: repeat(4, 1fr);
    gap: 6px;
  }

  .answer-item {
    height: 35px;
    font-size: 13px;
  }

  .feature-card h4 {
    font-size: 18px;
  }

  .feature-card p {
    font-size: 13px;
  }

  /* 超小屏幕熟练度统计 */
  .proficiency-stats-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
  }

  .proficiency-stats .stat-item {
    padding: 10px;
  }

  .proficiency-stats .stat-item .icon {
    font-size: 20px;
  }

  .proficiency-stats .stat-item .label {
    font-size: 12px;
  }

  .proficiency-stats .stat-item .count {
    font-size: 22px;
  }

  .quiz-number {
    font-size: 14px;
  }

  .option-btn {
    font-size: 14px;
    padding: 10px;
  }
}