/* 基本变量设置 */
  :root {
    --primary-color: #87CEEB; /* 天空蓝 */
    --secondary-color: #90EE90; /* 淡绿色 */
    --accent-color: #A9A9A9; /* 金属灰 */
    --gradient-start: #87CEEB;
    --gradient-end: #90EE90;
    --font-primary: 'Poppins', sans-serif;
    --font-secondary: 'Roboto', sans-serif;
    --max-width: 1200px;
  }

  /* 全局样式 */
  * {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }

  body {
    font-family: var(--font-primary);
    line-height: 1.6;
    background: linear-gradient(to right, var(--gradient-start), var(--gradient-end));
    color: #333;
    overflow-x: hidden;
  }

  img {
    max-width: 100%;
    height: auto;
    display: block;
  }

  a {
    color: var(--primary-color);
    text-decoration: none;
  }

  a:hover {
    text-decoration: underline;
  }

  /* 导航栏 */
  .navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.9);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    z-index: 1000;
  }

  .navbar-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 10px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
  }

  .navbar-logo {
    font-family: var(--font-secondary);
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
  }

  .navbar-menu {
    display: flex;
    gap: 20px;
  }

  .navbar-menu a {
    font-size: 1rem;
    font-weight: 500;
    transition: color 0.3s ease;
  }

  .navbar-menu a:hover {
    color: var(--secondary-color);
  }

  /* 侧边菜单 */
  .sidebar {
    position: fixed;
    top: 60px;
    left: -250px;
    width: 250px;
    height: 100%;
    background: #fff;
    box-shadow: 2px 0 5px rgba(0, 0, 0, 0.1);
    transition: left 0.3s ease;
    z-index: 999;
  }

  .sidebar.active {
    left: 0;
  }

  .sidebar ul {
    list-style: none;
    padding: 20px;
  }

  .sidebar ul li {
    margin-bottom: 15px;
  }

  .sidebar ul li a {
    color: #333;
    font-size: 1.1rem;
    transition: color 0.3s ease;
  }

  .sidebar ul li a:hover {
    color: var(--primary-color);
  }

  /* 主内容 */
  .main-content {
    padding-top: 70px;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 70px 20px 20px 20px;
  }

  .section {
    margin-bottom: 60px;
  }

  .section-title {
    font-family: var(--font-secondary);
    font-size: 2rem;
    margin-bottom: 20px;
    color: var(--primary-color);
    text-align: center;
  }

  .section-description {
    font-size: 1.1rem;
    line-height: 1.8;
    color: #555;
    text-align: center;
    max-width: 800px;
    margin: 0 auto 40px auto;
  }

  /* 模块 */
  .module-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
  }

  .module {
    background-color: #fff;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
  }

  .module:hover {
    transform: translateY(-10px);
    box-shadow: 0 10px 15px rgba(0, 0, 0, 0.2);
  }

  .module img {
    border-radius: 10px;
    margin-bottom: 15px;
  }

  .module h3 {
    font-family: var(--font-secondary);
    font-size: 1.5rem;
    margin-bottom: 10px;
    color: var(--secondary-color);
  }

  .module p {
    font-size: 1rem;
    color: #666;
  }

  /* 示例展示 */
  .example-display {
    background: rgba(255, 255, 255, 0.95);
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
  }

  .example-display h2 {
    font-family: var(--font-secondary);
    font-size: 1.8rem;
    margin-bottom: 20px;
    color: var(--accent-color);
    text-align: center;
  }

  .example-display p {
    font-size: 1rem;
    line-height: 1.8;
    color: #333;
    margin-bottom: 20px;
  }

  .example-display pre {
    background: #f4f4f4;
    padding: 15px;
    border-radius: 5px;
    overflow-x: auto;
    margin-bottom: 20px;
  }

  .example-display code {
    font-family: 'Courier New', Courier, monospace;
    color: #d63384;
  }

  .example-display table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 20px;
  }

  .example-display table, 
  .example-display th, 
  .example-display td {
    border: 1px solid #ddd;
  }

  .example-display th, 
  .example-display td {
    padding: 10px;
    text-align: left;
  }

  .example-display th {
    background-color: var(--secondary-color);
    color: #fff;
  }

  /* 提示文字 */
  .hint {
    text-align: center;
    font-size: 1rem;
    color: #ff5722;
    margin-bottom: 30px;
    font-weight: bold;
  }

  /* 图片展示 */
  .image-gallery {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
    margin-bottom: 40px;
  }

  .image-gallery img {
    width: 100px;
    height: 100px;
    object-fit: cover;
    border-radius: 5px;
    transition: transform 0.3s ease;
  }

  .image-gallery img:hover {
    transform: scale(1.1);
  }

  /* 响应式设计 */
  @media (max-width: 1440px) {
    .section-title {
      font-size: 1.8rem;
    }

    .navbar-container {
      padding: 10px 15px;
    }
  }

  @media (max-width: 1200px) {
    .navbar-menu {
      display: none;
    }

    .sidebar-toggle {
      display: block;
      cursor: pointer;
    }
  }

  @media (max-width: 1024px) {
    .section-description {
      padding: 0 10px;
    }
  }

  @media (max-width: 768px) {
    .module-container {
      grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    }

    .example-display {
      padding: 20px;
    }
  }

  @media (max-width: 480px) {
    .section-title {
      font-size: 1.5rem;
    }

    .module h3 {
      font-size: 1.3rem;
    }
  }

  @media (max-width: 320px) {
    .section-title {
      font-size: 1.2rem;
    }

    .navbar-logo {
      font-size: 1.2rem;
    }

    .module h3 {
      font-size: 1.1rem;
    }
  }

  /* 按钮样式 */
  .button {
    position: relative;
    display: inline-block;
    padding: 10px 20px;
    background-color: var(--primary-color);
    color: #fff;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    overflow: hidden;
    transition: background-color 0.3s ease;
  }

  .button:hover {
    background-color: var(--secondary-color);
  }

  .button::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.5);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    opacity: 0;
    transition: width 0.3s ease, height 0.3s ease, opacity 0.3s ease;
  }

  .button:hover::before {
    width: 200px;
    height: 200px;
    opacity: 1;
  }

  /* 底部样式 */
  footer {
    background: rgba(255, 255, 255, 0.9);
    padding: 20px 0;
    text-align: center;
    color: #666;
    font-size: 0.9rem;
  }

  footer a {
    color: var(--primary-color);
    margin: 0 10px;
  }

  footer a:hover {
    color: var(--secondary-color);
  }