/* Base styles */ body { font-family: Arial, sans-serif; margin: 0; padding: 0; } header { background-color: #4CAF50; color: white; padding: 1em; text-align: center; } main { padding: 1em; } /* Mobile styles */ @media (max-width: 600px) { header { font-size: 1.5em; } main { padding: 0.5em; } }