body {
    font-family: sans-serif;
    margin: 0;
    padding: 0;
    background-color: rgba(255, 255, 255, 0.5); 
  }
  
  
  header {
    background-color: #f0f0f0;
    padding: 20px;
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 100;
  }
  
  
  nav ul {
    list-style-type: none;
    text-align: center;
}

nav ul li {
    display: inline;
}

nav ul li a {
    color: #fff;
    text-decoration: none;
    padding: 10px 20px;
}

nav ul li a:hover {
    background-color: #555;
}
  
  
  .espacio-header {
    height: 40px; 
  }
  
  
  main {
    padding: 20px;
    margin-top: 45px;
  }
  
  
  .series {
    display: flex; 
    flex-wrap: wrap; 
    justify-content: space-between; 
  }
  
  .serie {
    width: 30%; 
    margin-bottom: 20px; 
    border: 1px solid #ccc; 
    padding: 15px;
  }
  
  .serie h2 {
    margin-top: 0; 
    font-size: 18px;
  }
  
  .serie p {
    margin-bottom: 0; 
    font-size: 14px;
  }
  
  
  @media (max-width: 768px) {
    .serie {
      width: 48%; 
    }
  }
  
  @media (max-width: 480px) {
    .serie {
      width: 100%; 
    }
  }

  footer {
    background-color: #333;
    color: #fff;
    text-align: center;
    padding: 10px 0;
    
  }