body {
  font-family: Arial, sans-serif;
  margin: 0;
  background: #f4f6f8;
}

header {
  background: #4da6ff;
  color: #1e3a5f; 
  padding: 15px;
  display: flex;
  align-items: center;
}

.logo {
  height: 50px;
  margin-right: 15px;
}

nav {
  background: #2c5d8a;
  padding: 10px;
  text-align: center;
}

nav button {
  margin: 5px;
  padding: 10px 20px;
  border: none;
  background: white;
  cursor: pointer;
  border-radius: 5px;
}

nav button:hover {
  background: #ddd;
}

main {
  padding: 20px;
}

.category {
  background: white;
  padding: 15px;
  border-radius: 8px;
}

.hidden {
  display: none;
}

a {
  color: #2c5d8a;
  text-decoration: none;
  font-weight: bold;
}

footer {
  text-align: center;
  padding: 10px;
  background: #1e3a5f;
  color: white;
  margin-top: 20px;
}