body {
    font-family: Arial, sans-serif;
    background-color: #f2f2f2;
  }
  
  .container {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-around;
  }
  
  .users, .membership-requests, .reserved-books,.livres {
    margin: 20px;
    background-color: #fff;
    border-radius: 5px;
    padding: 20px;
    box-shadow: 0 0 10px rgba(0, 0,0,0);
    
.navbar {
  float: right;
  margin-top: 20px;
}

.navbar ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
  overflow: hidden;
}

.navbar li {
  float: left;
}

.navbar li a {
  display: block;
  color: white;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
}

.navbar li a:hover {
  background-color: #111;
}