* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
  
  body {
    font-family: Arial, sans-serif;
    background-color: #f4f4f4;
    color: #333;
  }
  
  header {
    background-color: #4CAF50;
    color: white;
    padding: 20px;
    text-align: center;
  }
  
  .presentation-container {
    margin: 20px auto;
    text-align: center;
  }
  
  footer {
    background-color: #333;
    color: white;
    padding: 10px;
    text-align: center;
    position: fixed;
    width: 100%;
    bottom: 0;
  }
  
  iframe {
    border: none;
  }