body, html {
    margin: 0;
    padding: 0;
    font-family: 'Arial', sans-serif;
    background: #f7f7f7;
  }
  
  .container {
    width: 80%;
    margin: auto;
    padding-bottom: 20px;
  }
  
  .title {
    text-align: center;
    color: #333;
    margin: 20px 0;
  }
  
  .content {
    color: #666;
  }
  
  .lecture {
    margin-bottom: 30px; /* 增加每个讲座之间的间隔 */
    text-align: center;
  }
  
  .lecture-name {
    font-size: 24px;
    margin-bottom: 10px;
  }
  
  .lecture-links {
    margin-bottom: 10px;
  }
  
  .lecture-button, .button {
    padding: 10px 20px;
    font-size: 18px;
    color: white;
    background-color: #4CAF50;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    text-decoration: none;
    transition: background-color 0.3s ease;
    margin: 5px;
  }
  
  .lecture-button:hover, .button:hover {
    background-color: #367C2B;
  }
  
  .button {
    display: block;
    width: fit-content;
    margin: 40px auto 20px; /* 增加按钮的上边距 */
    background-color: #0056b3;
  }
  
  .button:hover {
    background-color: #004494;
  }
  
  .footer {
    text-align: center;
    margin-top: 60px;
  }