body {
  font-family: Arial, sans-serif;
  background: #f9f9f9;
  color: #333;
  margin: 0; padding: 0;
}
header {
  background: #003366;
  color: white;
  padding: 10px 20px;
}
nav ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
}
nav ul li {
  margin-right: 15px;
}
nav ul li a {
  color: white;
  text-decoration: none;
  font-weight: bold;
}
nav ul li a:hover {
  text-decoration: underline;
}
main {
  padding: 20px;
}
.book-item {
  background: white;
  padding: 10px;
  margin-bottom: 10px;
  border-radius: 5px;
  box-shadow: 1px 1px 5px rgba(0,0,0,0.1);
}