/* style.css - 现代化响应式设计 */

/* ====== 基础设置 ====== */
:root {
  /* 颜色变量 */
  --primary-color: #4361ee;
  --primary-hover: #3a56e7;
  --secondary-color: #3f8efc;
  --success-color: #2ec4b6;
  --danger-color: #e63946;
  --warning-color: #ffb703;
  --info-color: #4cc9f0;
  --light-color: #f8f9fa;
  --dark-color: #212529;
  --gray-100: #f8f9fa;
  --gray-200: #e9ecef;
  --gray-300: #dee2e6;
  --gray-400: #ced4da;
  --gray-500: #adb5bd;
  --gray-600: #6c757d;
  --gray-700: #495057;
  --gray-800: #343a40;
  --gray-900: #212529;
  
  /* 字体与尺寸 */
  --font-main: 'Roboto', 'Noto Sans SC', sans-serif;
  --border-radius: 0.5rem;
  --box-shadow: 0 0.5rem 1rem rgba(0, 0, 0, 0.1);
  --transition: all 0.3s ease;
}

    /* 添加Bootstrap类的自定义实现 */
    .badge {
      display: inline-block;
      padding: 0.25em 0.6em;
      font-size: 75%;
      font-weight: 700;
      line-height: 1;
      text-align: center;
      white-space: nowrap;
      vertical-align: baseline;
      border-radius: 0.25rem;
  }
  
  .bg-primary {
      background-color: #007bff !important;
      color: white;
  }
  
  .bg-success {
      background-color: #28a745 !important;
      color: white;
  }
  
  .bg-warning {
      background-color: #ffc107 !important;
      color: #212529;
  }
  
  .bg-secondary {
      background-color: #6c757d !important;
      color: white;
  }
  
  .bg-info {
      background-color: #17a2b8 !important;
      color: white;
  }
  
  .bg-danger {
      background-color: #dc3545 !important;
      color: white;
  }
  
  /* 定义CSS变量，用于题目样式 */
  :root {
      --primary-color: #007bff;
      --primary-rgb: 0, 123, 255;
      --success-color: #28a745;
      --success-rgb: 40, 167, 69;
      --warning-color: #ffc107;
      --warning-rgb: 255, 193, 7;
      --danger-color: #dc3545;
      --danger-rgb: 220, 53, 69;
      --gray-600: #6c757d;
      --border-color: #dee2e6;
      --border-radius: 0.25rem;
      --box-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
      --background-color: #f8f9fa;
  }
  

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-main);
  background: linear-gradient(135deg, #f0f7ff 0%, #eaf5ff 100%);
  color: var(--gray-800);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ====== 顶部导航栏 ====== */
nav {
  background-color: #fff;
  box-shadow: 0 2px 15px rgba(0, 0, 0, 0.08);
  padding: 0.8rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: sticky;
  top: 0;
  z-index: 1000;
  transition: var(--transition);
}

.nav-left {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
}

.nav-logo {
  color: var(--primary-color);
  font-size: 1.5rem;
  font-weight: 700;
  text-decoration: none;
  margin-right: 2rem;
  display: flex;
  align-items: center;
}

.nav-logo i {
  margin-right: 0.5rem;
}

.nav-links {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  justify-content: center; /* 电脑模式下剧中 */
  width: 100%;
}

.nav-link {
  color: var(--gray-700);
  text-decoration: none;
  font-size: 1rem;
  padding: 0.5rem 0.75rem;
  border-radius: var(--border-radius);
  transition: var(--transition);
}

.nav-link:hover {
  background-color: var(--gray-100);
  color: var(--primary-color);
}

.nav-link.active {
  background-color: var(--primary-color);
  color: white;
}

.nav-right .logout-link {
  background-color: var(--danger-color);
  padding: 0.5rem 1rem;
  border-radius: var(--border-radius);
  color: white;
  text-decoration: none;
  transition: var(--transition);
  display: inline-block;
}

.nav-right .logout-link:hover {
  background-color: #d32f2f;
  transform: translateY(-2px);
}

.menu-toggle {
  display: none;
  background: var(--primary-color);
  border: none;
  font-size: 1.5rem;
  color: white;
  cursor: pointer;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
  box-shadow: 0 2px 8px rgba(67, 97, 238, 0.3);
  z-index: 1001;
}

/* ====== 主内容容器 ====== */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 1.5rem;
  flex: 1;
}

.card {
  background-color: white;
  border-radius: var(--border-radius);
  box-shadow: var(--box-shadow);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  transition: var(--transition);
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 0.8rem 1.5rem rgba(0, 0, 0, 0.1);
}

.card-title {
  color: var(--gray-800);
  font-size: 1.5rem;
  margin-bottom: 1rem;
  font-weight: 600;
}

.card-subtitle {
  color: var(--gray-600);
  font-size: 1.1rem;
  margin-bottom: 1rem;
}

/* ====== 表单元素 ====== */
.form-group {
  margin-bottom: 1.5rem;
}

.form-label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 500;
  color: var(--gray-700);
}

.form-control {
  width: 100%;
  padding: 0.75rem 1rem;
  font-size: 1rem;
  line-height: 1.5;
  color: var(--gray-700);
  background-color: #fff;
  background-clip: padding-box;
  border: 1px solid var(--gray-300);
  border-radius: var(--border-radius);
  transition: var(--transition);
  -webkit-appearance: none; /* 移除iOS默认样式 */
  appearance: none;
  /* 移动端触摸优化 */
  touch-action: manipulation;
}

.form-control:focus {
  border-color: var(--primary-color);
  outline: 0;
  box-shadow: 0 0 0 0.2rem rgba(67, 97, 238, 0.25);
}

/* 输入框优化 */
input.form-control {
  min-height: 2.75rem; /* 确保触摸区域足够大 */
}

/* 为移动设备优化的选择框 */
select.form-control {
  cursor: pointer;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%236c757d' d='M3.5 4.5L6 7l2.5-2.5L10 6l-4 4-4-4z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1rem center;
  background-size: 0.75rem;
  padding-right: 2.5rem;
}

/* 为移动设备优化的复选框和单选框 */
.option-checkbox,
input[type="checkbox"],
input[type="radio"] {
  min-width: 1.25rem;
  min-height: 1.25rem;
  /* 确保足够大的触摸区域 */
}

/* 移动端表单布局优化 */
@media (max-width: 768px) {
  .form-row {
    flex-direction: column;
  }
  
  .form-group {
    margin-bottom: 1.25rem;
  }
  
  .form-control {
    font-size: 16px; /* 避免iOS缩放 */
    padding: 0.7rem 0.9rem;
  }
  
  /* 增大按钮间距，防止误触 */
  .btn + .btn {
    margin-top: 0.5rem;
    margin-left: 0 !important;
  }
}

/* 更小屏幕的表单元素优化 */
@media (max-width: 480px) {
  .form-control {
    padding: 0.65rem 0.85rem;
  }
  
  .form-label {
    font-size: 0.9rem;
  }
}

/* ====== 按钮样式 ====== */
.btn {
  display: inline-block;
  font-weight: 500;
  text-align: center;
  white-space: nowrap;
  vertical-align: middle;
  user-select: none;
  border: 1px solid transparent;
  padding: 0.75rem 1.5rem;
  font-size: 1rem;
  line-height: 1.5;
  border-radius: var(--border-radius);
  transition: var(--transition);
  cursor: pointer;
  /* 触摸优化 */
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
  position: relative;
  overflow: hidden;
  /* 确保移动端触摸区域足够大 */
  min-height: 2.75rem;
}

/* 添加触摸反馈效果 */
.btn::after {
  content: '';
  display: block;
  position: absolute;
  width: 100%;
  height: 100%;
  top: 0;
  left: 0;
  pointer-events: none;
  background-image: radial-gradient(circle, rgba(255, 255, 255, 0.3) 10%, transparent 10.01%);
  background-repeat: no-repeat;
  background-position: 50%;
  transform: scale(10, 10);
  opacity: 0;
  transition: transform 0.5s, opacity 0.8s;
}

.btn:active::after {
  transform: scale(0, 0);
  opacity: 0.3;
  transition: 0s;
}

.btn:focus {
  outline: 0;
  box-shadow: 0 0 0 0.2rem rgba(67, 97, 238, 0.25);
}

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

.btn-primary:hover {
  background-color: var(--primary-hover);
  border-color: var(--primary-hover);
  transform: translateY(-2px);
}

.btn-success {
  color: #fff;
  background-color: var(--success-color);
  border-color: var(--success-color);
}

.btn-success:hover {
  background-color: #25a99d;
  border-color: #25a99d;
  transform: translateY(-2px);
}

.btn-danger {
  color: #fff;
  background-color: var(--danger-color);
  border-color: var(--danger-color);
}

.btn-danger:hover {
  background-color: #d32f2f;
  border-color: #d32f2f;
  transform: translateY(-2px);
}

.btn-warning {
  color: #212529;
  background-color: var(--warning-color);
  border-color: var(--warning-color);
}

.btn-warning:hover {
  background-color: #e5a602;
  border-color: #e5a602;
  transform: translateY(-2px);
}

.btn-outline-primary {
  color: var(--primary-color);
  background-color: transparent;
  border-color: var(--primary-color);
}

.btn-outline-primary:hover {
  color: #fff;
  background-color: var(--primary-color);
  transform: translateY(-2px);
}

.btn-sm {
  padding: 0.5rem 1rem;
  font-size: 0.875rem;
  min-height: 2.25rem;
}

.btn-lg {
  padding: 1rem 2rem;
  font-size: 1.25rem;
  min-height: 3.25rem;
}

.btn-block {
  display: block;
  width: 100%;
}

/* 移动端按钮优化 */
@media (max-width: 768px) {
  .btn {
    padding: 0.7rem 1.25rem;
  }
  
  /* 增大按钮之间的间距以避免误触 */
  .btn + .btn {
    margin-top: 0.75rem;
  }
  
  /* 移动端交互元素适配 */
  .card-actions .btn,
  .question-actions .btn {
    width: 100%;
    margin-bottom: 0.5rem;
  }
}

/* 更小屏幕的按钮优化 */
@media (max-width: 480px) {
  .btn {
    padding: 0.65rem 1.15rem;
    font-size: 0.95rem;
  }
  
  .btn-sm {
    padding: 0.45rem 0.9rem;
    font-size: 0.85rem;
  }
  
  .btn-lg {
    padding: 0.9rem 1.75rem;
    font-size: 1.1rem;
  }
}

/* ====== 徽章 ====== */
.badge {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  font-size: 0.875rem;
  font-weight: 500;
  line-height: 1;
  text-align: center;
  white-space: nowrap;
  vertical-align: baseline;
  border-radius: 50rem;
}

.badge-primary { background-color: var(--primary-color); color: white; }
.badge-success { background-color: var(--success-color); color: white; }
.badge-danger { background-color: var(--danger-color); color: white; }
.badge-warning { background-color: var(--warning-color); color: var(--gray-800); }
.badge-info { background-color: var(--info-color); color: white; }

/* ====== 答题页面样式 ====== */
.question-container {
  background-color: white;
  border-radius: var(--border-radius);
  box-shadow: var(--box-shadow);
  padding: 2rem;
  margin-bottom: 2rem;
}

.question-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.5rem;
}

.question-number {
  display: inline-block;
  padding: 0.35rem 0.75rem;
  font-size: 1rem;
  font-weight: 600;
  color: white;
  background-color: var(--primary-color);
  border-radius: var(--border-radius);
}

.question-difficulty {
  padding: 0.35rem 0.75rem;
  border-radius: var(--border-radius);
  font-weight: 500;
}

.difficulty-easy { background-color: #a3e635; color: var(--gray-800); }
.difficulty-medium { background-color: #facc15; color: var(--gray-800); }
.difficulty-hard { background-color: #f87171; color: white; }

.question-stem {
  font-size: 1.2rem;
  line-height: 1.7;
  margin-bottom: 2rem;
  color: var(--gray-800);
}

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

.option-item {
  margin-bottom: 1rem;
}

.option-label {
  display: flex;
  align-items: center;
  padding: 1rem;
  background-color: var(--gray-100);
  border: 1px solid var(--gray-300);
  border-radius: var(--border-radius);
  cursor: pointer;
  transition: var(--transition);
  /* 移动端触摸优化 */
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
  position: relative;
  overflow: hidden;
}

/* 添加触摸反馈效果 */
.option-label::after {
  content: '';
  display: block;
  position: absolute;
  width: 100%;
  height: 100%;
  top: 0;
  left: 0;
  pointer-events: none;
  background-image: radial-gradient(circle, rgba(67, 97, 238, 0.1) 10%, transparent 10.01%);
  background-repeat: no-repeat;
  background-position: 50%;
  transform: scale(10, 10);
  opacity: 0;
  transition: transform 0.5s, opacity 0.8s;
}

.option-label:active::after {
  transform: scale(0, 0);
  opacity: 0.3;
  transition: 0s;
}

.option-label:hover {
  background-color: var(--gray-200);
}

/* 选中状态增强 */
.option-item input:checked + .option-text {
  font-weight: 500;
  color: var(--primary-color);
}

.option-item input:checked ~ .option-label {
  background-color: rgba(67, 97, 238, 0.05);
  border-color: var(--primary-color);
  box-shadow: 0 0 0 1px var(--primary-color);
}

.option-checkbox {
  margin-right: 1rem;
  transform: scale(1.2);
  /* 移动端触摸优化 */
  min-width: 1.5rem;
  min-height: 1.5rem;
}

.option-text {
  flex: 1;
}

/* 移动设备优化 */
@media (max-width: 768px) {
  .option-label {
    padding: 0.875rem;
  }
  
  .option-checkbox {
    transform: scale(1.3);
    margin-right: 0.75rem;
  }
}

@media (max-width: 480px) {
  .option-label {
    padding: 0.75rem;
  }
  
  .option-text {
    font-size: 0.95rem;
  }
}

.question-actions {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 2rem;
}

.favorite-btn {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  background-color: white;
  border: 1px solid var(--gray-300);
  border-radius: var(--border-radius);
  padding: 0.5rem 1rem;
  cursor: pointer;
  transition: var(--transition);
}

.favorite-btn:hover {
  background-color: var(--gray-100);
}

.favorite-btn.active {
  background-color: var(--warning-color);
  border-color: var(--warning-color);
  color: var(--gray-800);
}

.result-message {
  margin: 1.5rem 0;
  padding: 1rem;
  border-radius: var(--border-radius);
  font-weight: 500;
}

.result-correct {
  background-color: rgba(46, 196, 182, 0.2);
  color: #1a8a7e;
  border-left: 4px solid var(--success-color);
}

.result-incorrect {
  background-color: rgba(230, 57, 70, 0.2);
  color: #b71c1c;
  border-left: 4px solid var(--danger-color);
}

/* ====== 进度条 ====== */
.progress-container {
  margin-bottom: 2rem;
}

.progress-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.75rem;
}

.progress-title {
  font-weight: 500;
  color: var(--gray-700);
}

.progress-value {
  font-weight: 600;
  color: var(--primary-color);
}

.progress-bar-container {
  width: 100%;
  height: 0.75rem;
  background-color: var(--gray-200);
  border-radius: 1rem;
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  background-color: var(--primary-color);
  border-radius: 1rem;
  transition: width 0.3s ease;
}

/* ====== 表格样式 ====== */
.table-container {
  overflow-x: auto;
  margin-bottom: 2rem;
  /* 添加移动端水平滚动支持 */
  -webkit-overflow-scrolling: touch;
  position: relative;
}

/* 添加滚动指示器 */
.table-container::after {
  content: '';
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  width: 20px;
  background: linear-gradient(to right, rgba(255, 255, 255, 0), rgba(0, 0, 0, 0.05));
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.3s;
}

/* 仅在可滚动且非移动设备上显示滚动指示器 */
@media (min-width: 769px) {
  .table-container.is-scrollable::after {
    opacity: 1;
  }
}

.table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1rem;
  /* 确保表格在移动设备上不会被压缩 */
  table-layout: fixed;
}

.table th,
.table td {
  padding: 1rem;
  text-align: left;
  border-bottom: 1px solid var(--gray-300);
  /* 移动端文本处理 */
  word-wrap: break-word;
  overflow-wrap: break-word;
}

.table th {
  font-weight: 600;
  color: var(--gray-700);
  background-color: var(--gray-100);
  /* 粘性表头，在水平滚动时保持可见 */
  position: sticky;
  top: 0;
  z-index: 10;
}

.table tbody tr {
  transition: var(--transition);
}

.table tbody tr:hover {
  background-color: rgba(67, 97, 238, 0.05);
}

/* 响应式表格 - 移动优化 */
@media (max-width: 768px) {
  .table-container {
    margin-left: -1rem;
    margin-right: -1rem;
    width: calc(100% + 2rem);
    padding: 0 1rem;
    /* 添加滚动提示 */
    scrollbar-width: thin;
    scrollbar-color: var(--gray-300) transparent;
  }
  
  .table th,
  .table td {
    padding: 0.85rem 0.75rem;
    font-size: 0.95rem;
  }
  
  /* 特定表格列宽调整 - 适用于答题历史表格 */
  .table th:nth-child(1), 
  .table td:nth-child(1) {
    width: 40px;
    min-width: 40px;
  }
  
  .table th:nth-child(2), 
  .table td:nth-child(2) {
    width: 60px;
    min-width: 60px;
  }
  
  .table th:nth-child(3), 
  .table td:nth-child(3) {
    width: auto;
    min-width: 120px;
  }
  
  .table th:nth-child(4), 
  .table td:nth-child(4) {
    width: 60px;
    min-width: 60px;
  }
  
  .table th:nth-child(5), 
  .table td:nth-child(5) {
    width: 80px;
    min-width: 60px;
  }
  
  .table th:nth-child(6), 
  .table td:nth-child(6) {
    width: 100px;
    min-width: 100px;
  }
  
  /* 为小屏幕添加水平滚动提示 */
  .table-scroll-hint {
    display: block;
    text-align: center;
    color: var(--gray-600);
    font-size: 0.85rem;
    margin-bottom: 0.5rem;
    opacity: 0.7;
  }
  
  /* 卡片式移动表格 - 用于特定表格 */
  .table.table-card-mobile {
    border: 0;
  }
  
  .table.table-card-mobile thead {
    display: none; /* 隐藏表头 */
  }
  
  .table.table-card-mobile tr {
    display: block;
    margin-bottom: 1rem;
    border: 1px solid var(--gray-300);
    border-radius: var(--border-radius);
  }
  
  .table.table-card-mobile td {
    display: block;
    text-align: right;
    border-bottom: 1px solid var(--gray-200);
    position: relative;
    padding-left: 50%;
  }
  
  .table.table-card-mobile td:last-child {
    border-bottom: 0;
  }
  
  .table.table-card-mobile td::before {
    content: attr(data-label);
    position: absolute;
    left: 0.75rem;
    width: 45%;
    text-align: left;
    font-weight: 600;
    color: var(--gray-700);
  }
}

@media (max-width: 480px) {
  .table th,
  .table td {
    padding: 0.75rem 0.5rem;
    font-size: 0.9rem;
  }
  
  .nav-right .logout-link {
    width: 95%;
  }
}

/* ====== 卡片样式 ====== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
}

.stat-card {
  background-color: white;
  border-radius: var(--border-radius);
  box-shadow: var(--box-shadow);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  transition: var(--transition);
}

.stat-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 0.8rem 1.5rem rgba(0, 0, 0, 0.1);
}

.stat-icon {
  width: 3rem;
  height: 3rem;
  background-color: rgba(67, 97, 238, 0.1);
  color: var(--primary-color);
  display: flex;
  justify-content: center;
  align-items: center;
  border-radius: 50%;
  margin-bottom: 1rem;
  font-size: 1.5rem;
}

.stat-value {
  font-size: 2rem;
  font-weight: 700;
  color: var(--gray-800);
  margin-bottom: 0.5rem;
}

.stat-label {
  color: var(--gray-600);
  font-size: 1rem;
}

/* ====== 登录/注册页面 ====== */
.auth-container {
  max-width: 400px;
  margin: 2rem auto;
  padding: 2rem;
  background-color: white;
  border-radius: var(--border-radius);
  box-shadow: var(--box-shadow);
}

.auth-logo {
  text-align: center;
  margin-bottom: 2rem;
}

.auth-title {
  text-align: center;
  color: var(--gray-800);
  font-size: 1.75rem;
  margin-bottom: 2rem;
}

.auth-form {
  margin-bottom: 1.5rem;
}

.auth-footer {
  text-align: center;
  margin-top: 1.5rem;
}

.auth-footer a {
  color: var(--primary-color);
  text-decoration: none;
  font-weight: 500;
}

.auth-footer a:hover {
  text-decoration: underline;
}

/* ====== 提醒消息 ====== */
.alert {
  padding: 1rem;
  margin-bottom: 1.5rem;
  border-radius: var(--border-radius);
  font-weight: 500;
}

.alert-success {
  background-color: rgba(46, 196, 182, 0.2);
  color: #1a8a7e;
  border-left: 4px solid var(--success-color);
}

.alert-danger {
  background-color: rgba(230, 57, 70, 0.2);
  color: #b71c1c;
  border-left: 4px solid var(--danger-color);
}

.alert-warning {
  background-color: rgba(255, 183, 3, 0.2);
  color: #9c6d00;
  border-left: 4px solid var(--warning-color);
}

.alert-info {
  background-color: rgba(76, 201, 240, 0.2);
  color: #0277bd;
  border-left: 4px solid var(--info-color);
}

/* ====== 倒计时样式 ====== */
.countdown-container {
  background-color: white;
  border-radius: var(--border-radius);
  box-shadow: var(--box-shadow);
  padding: 1.5rem;
  text-align: center;
  margin-bottom: 2rem;
}

.countdown-title {
  color: var(--gray-700);
  font-size: 1.2rem;
  margin-bottom: 1rem;
}

.countdown-timer {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--primary-color);
}

.countdown-warning {
  color: var(--warning-color);
}

.countdown-danger {
  color: var(--danger-color);
}

/* ====== 页脚样式 ====== */
.footer {
  background-color: white;
  padding: 2rem 0;
  margin-top: auto;
  text-align: center;
  border-top: 1px solid var(--gray-200);
}

.footer-text {
  color: var(--gray-600);
  font-size: 0.875rem;
}

.footer-link {
  color: var(--primary-color);
  text-decoration: none;
  font-weight: 500;
}

.footer-link:hover {
  text-decoration: underline;
}

/* ====== 响应式设计 ====== */
@media (max-width: 992px) {
  .nav-left {
    gap: 0.5rem;
  }
  
  .nav-link {
    padding: 0.4rem 0.6rem;
    font-size: 0.9rem;
  }
  
  .card-grid {
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  }
  
  .stat-value {
    font-size: 1.8rem;
  }
}

@media (max-width: 768px) {
  .nav {
    flex-direction: column;
    align-items: flex-start;
    padding: 1rem;
  }
  
  .nav-logo {
    margin-right: 0;
    margin-bottom: 0.5rem;
  }
  
  .nav-links {
    display: none;
    width: 100%;
    flex-direction: column;
    margin-top: 1.5rem;
    flex-wrap: nowrap;
    background: white;
    border-radius: 12px;
    padding: 0.75rem;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    max-height: 70vh;
    overflow-y: auto;
    position: absolute;
    right: 1rem;
    width: auto;
    min-width: 200px;
    max-width: 80%;
    top: 3.5rem;
    /* 添加平滑滚动 */
    scroll-behavior: smooth;
    /* 美化滚动条 */
    scrollbar-width: thin;
    scrollbar-color: var(--gray-300) transparent;
  }
  
  .nav-links::-webkit-scrollbar {
    width: 6px;
  }
  
  .nav-links::-webkit-scrollbar-track {
    background: transparent;
  }
  
  .nav-links::-webkit-scrollbar-thumb {
    background-color: var(--gray-300);
    border-radius: 10px;
  }
  
  /* 菜单打开时添加背景遮罩 */
  .menu-backdrop {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.4);
    z-index: 999;
    backdrop-filter: blur(2px);
    opacity: 0;
    transition: opacity 0.3s ease;
  }
  
  .menu-backdrop.active {
    display: block;
    opacity: 1;
  }
  
  .nav-links.active {
    display: flex;
    animation: slideDown 0.3s ease-out forwards;
    position: relative;
    z-index: 1000;
  }
  
  @keyframes slideDown {
    from {
      opacity: 0;
      transform: translateY(-10px);
    }
    to {
      opacity: 1;
      transform: translateY(0);
    }
  }
  
  .nav-link {
    padding: 1rem;
    width: 100%;
    border-radius: 8px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    display: flex;
    align-items: center;
    margin-bottom: 0.5rem;
    font-weight: 500;
    transition: all 0.2s ease;
    background-color: var(--gray-100);
  }
  
  .nav-link i {
    margin-right: 0.75rem;
    font-size: 1.1rem;
    width: 24px;
    text-align: center;
    color: var(--primary-color);
  }
  
  .nav-link:last-child {
    margin-bottom: 0;
  }
  
  .nav-link:hover {
    background-color: var(--gray-200);
    transform: translateX(3px);
  }
  
  .nav-link.active {
    background-color: var(--primary-color);
    color: white;
    box-shadow: 0 4px 10px rgba(67, 97, 238, 0.25);
  }
  
  .nav-link.active i {
    color: white;
  }
  
  .menu-toggle {
    display: flex;
    position: absolute;
    top: 1rem;
    right: 1rem;
    transform: scale(1);
  }
  
  .menu-toggle:active {
    transform: scale(0.92);
  }
  
  .nav-right {
    width: 100%;
    margin-top: 1.25rem;
    display: flex;
    justify-content: center;
    padding: 0 1rem;
    box-sizing: border-box;
  }
  
  .nav-right .logout-link {
    width: 100%;
    padding: 0.8rem 1rem;
    text-align: center;
    font-size: 0.95rem;
    font-weight: 500;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 0.5rem;
    margin: 0 auto;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  }
  
  .question-actions {
    flex-direction: column;
    gap: 1rem;
  }
  
  .question-actions button {
    width: 100%;
  }
  
  .card-grid {
    grid-template-columns: 1fr;
  }
  
  .question-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
  }
  
  .table-container {
    margin-left: -1rem;
    margin-right: -1rem;
    width: calc(100% + 2rem);
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    padding: 0 1rem;
  }
  
  .option-label {
    padding: 0.875rem;
  }
  
  .option-checkbox {
    min-width: 20px;
  }
  
  .pagination {
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.5rem;
  }
}

@media (max-width: 576px) {
  body {
    font-size: 15px;
  }
  
  .container {
    padding: 1rem;
  }
  
  .card, .question-container {
    padding: 1.25rem;
  }
  
  .card-title {
    font-size: 1.35rem;
  }
  
  .auth-container {
    margin: 1rem;
    max-width: none;
  }
  
  .question-stem {
    font-size: 1.05rem;
  }
  
  .option-label {
    padding: 0.75rem;
  }
  
  .stat-value {
    font-size: 1.65rem;
  }
  
  .countdown-timer {
    font-size: 1.85rem;
  }
  
  .table th, .table td {
    padding: 0.75rem 0.5rem;
    font-size: 0.9rem;
  }
  
  .btn {
    padding: 0.65rem 1.25rem;
  }
  
  .btn-block {
    width: 100%;
  }
  
  .form-control {
    padding: 0.65rem 0.875rem;
    font-size: 0.95rem;
  }
  
  .footer {
    padding: 1.5rem 0;
  }
  
  .footer-text {
    font-size: 0.8rem;
  }
}

/* 更多手机端优化 */
@media (max-width: 480px) {
  body {
    font-size: 14px;
  }
  
  .container {
    padding: 0.85rem;
  }
  
  .card, .question-container {
    padding: 1rem;
    margin-bottom: 1.25rem;
  }
  
  .card-title {
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
  }
  
  .question-stem {
    font-size: 1rem;
    margin-bottom: 1.5rem;
  }
  
  .option-label {
    padding: 0.625rem;
  }
  
  .option-checkbox {
    transform: scale(1.1);
  }
  
  .btn {
    padding: 0.6rem 1.2rem;
    font-size: 0.95rem;
  }
  
  .badge {
    padding: 0.2rem 0.5rem;
    font-size: 0.8rem;
  }
  
  .alert {
    padding: 0.85rem;
    margin-bottom: 1.25rem;
  }
  
  .stat-card {
    padding: 1.25rem;
  }
  
  .stat-value {
    font-size: 1.5rem;
  }
  
  .stat-icon {
    width: 2.5rem;
    height: 2.5rem;
    font-size: 1.25rem;
  }
  
  .auth-container {
    padding: 1.5rem 1rem;
  }
  
  .auth-title {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
  }
  
  .countdown-timer {
    font-size: 1.75rem;
  }
  
  /* 更小屏幕的导航菜单优化 */
  .nav-links {
    margin-top: 1.25rem;
    padding: 0.65rem;
    max-height: 65vh;
    right: 0.85rem;
  }
  
  .nav-link {
    padding: 0.85rem;
    font-size: 0.95rem;
    margin-bottom: 0.4rem;
    text-align: left;
  }
  
  .nav-link i {
    margin-right: 0.6rem;
    font-size: 1rem;
    width: 20px;
  }
  
  .menu-toggle {
    width: 38px;
    height: 38px;
    font-size: 1.35rem;
    top: 0.85rem;
    right: 0.85rem;
  }
}

/* ====== 主题色变量自定义 ====== */
[data-theme="blue"] {
  --primary-color: #4361ee;
  --primary-hover: #3a56e7;
}

[data-theme="green"] {
  --primary-color: #2ec4b6;
  --primary-hover: #25a99d;
}

[data-theme="purple"] {
  --primary-color: #7209b7;
  --primary-hover: #5f08a0;
}

[data-theme="orange"] {
  --primary-color: #fb8500;
  --primary-hover: #e67700;
}

/* ====== 翻页样式 ====== */
.pagination {
  display: flex;
  padding-left: 0;
  list-style: none;
  border-radius: var(--border-radius);
  margin-bottom: 1rem;
}

.page-item {
  position: relative;
  display: block;
}

.page-item:not(:first-child) .page-link {
  margin-left: -1px;
}

.page-item.active .page-link {
  z-index: 3;
  color: #fff;
  background-color: var(--primary-color);
  border-color: var(--primary-color);
}

.page-item.disabled .page-link {
  color: #6c757d;
  pointer-events: none;
  background-color: #fff;
  border-color: #dee2e6;
}

.page-link {
  position: relative;
  display: block;
  color: var(--primary-color);
  text-decoration: none;
  background-color: #fff;
  border: 1px solid #dee2e6;
  transition: color 0.15s ease-in-out, background-color 0.15s ease-in-out, border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
  padding: 0.375rem 0.75rem;
  margin-left: -1px;
  line-height: 1.25;
}

.page-link:hover {
  z-index: 2;
  color: var(--primary-hover);
  text-decoration: none;
  background-color: #e9ecef;
  border-color: #dee2e6;
}

.page-link:focus {
  z-index: 3;
  color: var(--primary-hover);
  background-color: #e9ecef;
  border-color: #86b7fe;
  outline: 0;
  box-shadow: 0 0 0 0.25rem rgba(67, 97, 238, 0.25);
}

.page-item:first-child .page-link {
  border-top-left-radius: var(--border-radius);
  border-bottom-left-radius: var(--border-radius);
}

.page-item:last-child .page-link {
  border-top-right-radius: var(--border-radius);
  border-bottom-right-radius: var(--border-radius);
}

.pagination-lg .page-link {
  padding: 0.75rem 1.5rem;
  font-size: 1.25rem;
}

.pagination-sm .page-link {
  padding: 0.25rem 0.5rem;
  font-size: 0.875rem;
}

/* ====== 答题历史记录文本限制 ====== */
.question-text-truncate {
  display: block;
  max-width: 100%;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* 移动端答题历史文本限制 */
@media (max-width: 768px) {
  .question-text-truncate {
    max-width: 150px;
  }
}

@media (max-width: 576px) {
  .question-text-truncate {
    max-width: 120px;
  }
}

@media (max-width: 480px) {
  .question-text-truncate {
    max-width: 100px;
  }
}

/* ====== 辅助工具类 ====== */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }
.text-decoration-none { text-decoration: none !important; }

/* Margin utilities */
.mb-0 { margin-bottom: 0 !important; }
.mb-1 { margin-bottom: 0.5rem !important; }
.mb-2 { margin-bottom: 1rem !important; }
.mb-3 { margin-bottom: 1.5rem !important; }
.mb-4 { margin-bottom: 2rem !important; }
.mt-0 { margin-top: 0 !important; }
.mt-1 { margin-top: 0.5rem !important; }
.mt-2 { margin-top: 1rem !important; }
.mt-3 { margin-top: 1.5rem !important; }
.mt-4 { margin-top: 2rem !important; }
.me-1 { margin-right: 0.5rem !important; }
.me-2 { margin-right: 1rem !important; }
.me-3 { margin-right: 1.5rem !important; }
.ms-1 { margin-left: 0.5rem !important; }
.ms-2 { margin-left: 1rem !important; }
.ms-3 { margin-left: 1.5rem !important; }
.mx-auto { margin-left: auto !important; margin-right: auto !important; }

/* Padding utilities */
.p-0 { padding: 0 !important; }
.p-1 { padding: 0.5rem !important; }
.p-2 { padding: 1rem !important; }
.p-3 { padding: 1.5rem !important; }

/* Display utilities */
.d-none { display: none !important; }
.d-block { display: block !important; }
.d-inline { display: inline !important; }
.d-inline-block { display: inline-block !important; }
.d-flex { display: flex !important; }
.d-inline-flex { display: inline-flex !important; }

/* Responsive display utilities */
@media (min-width: 576px) {
  .d-sm-none { display: none !important; }
  .d-sm-block { display: block !important; }
  .d-sm-flex { display: flex !important; }
}

@media (min-width: 768px) {
  .d-md-none { display: none !important; }
  .d-md-block { display: block !important; }
  .d-md-flex { display: flex !important; }
}

@media (min-width: 992px) {
  .d-lg-none { display: none !important; }
  .d-lg-block { display: block !important; }
  .d-lg-flex { display: flex !important; }
}

/* Flexbox utilities */
.flex-row { flex-direction: row !important; }
.flex-column { flex-direction: column !important; }
.flex-wrap { flex-wrap: wrap !important; }
.flex-nowrap { flex-wrap: nowrap !important; }
.justify-content-start { justify-content: flex-start !important; }
.justify-content-end { justify-content: flex-end !important; }
.justify-content-center { justify-content: center !important; }
.justify-content-between { justify-content: space-between !important; }
.justify-content-around { justify-content: space-around !important; }
.align-items-start { align-items: flex-start !important; }
.align-items-end { align-items: flex-end !important; }
.align-items-center { align-items: center !important; }
.align-items-baseline { align-items: baseline !important; }
.align-items-stretch { align-items: stretch !important; }

/* Gap utilities */
.gap-1 { gap: 0.5rem !important; }
.gap-2 { gap: 1rem !important; }
.gap-3 { gap: 1.5rem !important; }

/* Width utilities */
.w-25 { width: 25% !important; }
.w-50 { width: 50% !important; }
.w-75 { width: 75% !important; }
.w-100 { width: 100% !important; }
.w-auto { width: auto !important; }

/* Font utilities */
.font-weight-bold { font-weight: 700 !important; }
.font-weight-normal { font-weight: 400 !important; }
.fw-bold { font-weight: 700 !important; }
.fw-normal { font-weight: 400 !important; }

/* Text color utilities */
.text-primary { color: var(--primary-color) !important; }
.text-success { color: var(--success-color) !important; }
.text-danger { color: var(--danger-color) !important; }
.text-warning { color: var(--warning-color) !important; }
.text-info { color: var(--info-color) !important; }
.text-muted { color: var(--gray-600) !important; }

/* Position utilities */
.position-relative { position: relative !important; }
.position-absolute { position: absolute !important; }
.position-fixed { position: fixed !important; }
.position-sticky { position: sticky !important; }

/* 响应式显示类 */
.mobile-only {
  display: none;
}

/* 移动端全宽元素 */
.mobile-full-width {
  width: auto;
}

@media (max-width: 768px) {
  .mobile-only {
    display: block;
  }
  
  .desktop-only {
    display: none;
  }
  
  .mobile-full-width {
    width: 90% !important;
  }
}

@media (max-width: 480px) {
  .mobile-full-width {
    width: 95% !important;
  }
}