/* Basic Reset */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: Arial, sans-serif;
}

body {
  background-color: #f4f4f9;
  color: #333;
}

header {
  background-color: #4a90e2;
  color: white;
  padding: 20px 0;
  text-align: center;
}

nav ul {
  display: flex;
  justify-content: center;
  list-style: none;
  margin-top: 10px;
}

nav ul li {
  margin: 0 20px;
  cursor: pointer;
  padding: 5px 10px;
  border-radius: 5px;
  transition: background-color 0.3s;
}

nav ul li:hover {
  background-color: rgba(255, 255, 255, 0.3);
}

nav ul li.active {
  background-color: rgba(255, 255, 255, 0.5);
}

main {
  padding: 40px 20px;
  max-width: 800px;
  margin: auto;
}

.tab-content {
  display: none;
}

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