/* General styles */
body {
  font-family: Arial, sans-serif;
  margin: 20px;
  background: #f2f5f3;
  color: #222;
}

header {
  background: #3c817c;
  color: #fff;
  padding: 16px;
  margin-bottom: 24px;
  text-align: center;
  border-radius: 6px;
}

nav {
  margin-top: 12px;
}

nav a {
  color: #fff;
  margin-right: 16px;
  text-decoration: none;
  font-weight: bold;
}

section {
  background: #fff;
  padding: 16px;
  border-radius: 8px;
  margin-bottom: 24px;
  box-shadow: 0 2px 8px #eee;
}

/* Responsive design using media queries */
@media (max-width: 800px) {
  header h1 {
    font-size: 2rem;
  }
  nav a {
    margin-right: 10px;
    font-size: 1rem;
  }
}

@media (max-width: 500px) {
  body {
    margin: 5px;
    font-size: 1rem;
  }
  header h1 {
    font-size: 1.2rem;
  }
  nav {
    display: block;
  }
  nav a {
    display: block;
    margin: 8px 0;
  }
  section {
    padding: 8px;
    margin-bottom: 12px;
  }
}

/* Desktop layout */
@media (min-width: 801px) {
  main {
    max-width: 800px;
    margin: auto;
  }
}