body { font-family: Arial, sans-serif; margin: 0; padding: 0; text-align: center; }
header { background: #333; color: #fff; padding: 1em; }
main { padding: 2em; }
footer { background: #f4f4f4; padding: 1em; }
.btn { display: inline-block; margin: 10px; padding: 10px 20px; background: #007bff; color: #fff; text-decoration: none; border-radius: 5px; }