body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  background-color: #121212;
  color: #ffffff;
}

header {
  background-color: #1f1f1f;
  padding: 20px;
  text-align: center;
}

nav {
  display: flex;
  justify-content: center;
  background-color: #2c2c2c;
  padding: 10px;
}

nav button {
  background-color: #3b3b3b;
  color: white;
  border: none;
  margin: 0 10px;
  padding: 10px 20px;
  cursor: pointer;
  border-radius: 8px;
  transition: background-color 0.2s;
}

nav button:hover {
  background-color: #505050;
}

main {
  padding: 20px;
}

.content-section {
  display: none;
}

.content-section.active {
  display: block;
}

footer {
  text-align: center;
  padding: 20px;
  background-color: #1f1f1f;
  color: #aaa;
}