<style>
body {
  font-family: Arial, sans-serif;
  margin: 0;
  background: #f4f7fb;
  color: #1f2937;
}

header {
  background: #0b2a4a;
  padding: 15px;
}

nav {
  display: flex;
  gap: 15px;
  justify-content: center;
}

nav a {
  color: #fff;
  text-decoration: none;
}

.container {
  max-width: 1100px;
  margin: auto;
  padding: 40px 20px;
}

.box {
  background: #fff;
  padding: 25px;
  border-radius: 12px;
  margin-top: 20px;
}
</style>