index2.css

body {
  margin: 0;
  padding: 0;
}

header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background-color: #333;
  color: #fff;
}

nav ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
}

nav ul li {
  display: inline-block;
}

nav ul li a {
  display: block;
  padding: 15px 20px;
  color: #fff;
  text-decoration: none;
}

nav ul li a:hover {
  background-color: #555;
}
.container {
    width: 800px;
    margin: 50px auto;
    background-color: #f2f2f2;
    padding: 20px;
  }
  
  .content {
    text-align: center;
  }
  
  .content h2 {
    color: #333;
  }
  
  .content p {
    color: #666;
  }
  
  .content img {
    max-width: 100%;
    margin-top: 20px;
  }