body { 
    font-family: Arial, sans-serif, system-ui; 
    margin: 40px; 
    background-color: #FFF9E5;
}
@media (max-width: 640px) {
    body { font-size: 18px; margin: 12px; }
    h1 { font-size: 24px; }
    h2 { font-size: 18px; }
}