body { font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; }
.card { max-width: 800px; margin: 0 auto; }
.form-range { height: 40px; }
output { font-weight: bold; font-size: 1.2em; color: #007bff; }
@media (max-width: 768px) {
    .container { padding: 1rem; }
    .card { margin: 0 1rem; }
}