:root {
  --primary-color: #3b82f6;
  --secondary-color: #10b981;
  --background-color: #f0f4f8;
  --text-color: #1f2937;
  --card-background: #ffffff;
  --shadow-color: rgba(0, 0, 0, 0.1);
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--background-color);
  color: var(--text-color);
  margin: 0;
  padding: 0;
  background-image: url('data:image/svg+xml,%3Csvg width="6" height="6" viewBox="0 0 6 6" xmlns="http://www.w3.org/2000/svg"%3E%3Cg fill="%239C92AC" fill-opacity="0.1"%3E%3Cpath d="M5 0h1L0 6V5zM6 5v1H0V5z"/%3E%3C/g%3E%3C/svg%3E');
}

header {
  background-color: var(--primary-color);
  color: white;
  padding: 1rem 2rem;
  box-shadow: 0 4px 6px var(--shadow-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

header h1 {
  margin: 0;
  font-size: 1.5rem;
}

nav a {
  color: white;
  text-decoration: none;
  margin-left: 1rem;
  transition: color 0.3s ease;
}

nav a:hover {
  color: var(--secondary-color);
}

main {
  padding: 2rem;
  display: grid;
  gap: 2rem;
  justify-content: center;
}

.card {
  background-color: var(--card-background);
  border-radius: 8px;
  padding: 1.5rem;
  box-shadow: 0 10px 15px -3px var(--shadow-color), 0 4px 6px -2px var(--shadow-color);
  max-width: 500px;
}

footer {
  text-align: center;
  padding: 1rem;
  margin-top: 2rem;
  color: #6b7280;
}

@media (max-width: 600px) {
  header {
    flex-direction: column;
  }

  header h1 {
    margin-bottom: 1rem;
  }
}