body {
    font-family: system-ui, -apple-system, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f8fafc;
    color: #1e293b;
}
header {
    background-color: #0f172a;
    color: white;
    padding: 2rem;
    text-align: center;
}
main {
    max-width: 800px;
    margin: 2rem auto;
    padding: 0 1rem;
}
.card {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}