body {
    font-family: Arial, sans-serif;
    margin: 0;
    background-color: #f4f7f9;
    color: #333;
}
header {
    background-color: #4CAF50;
    color: white;
    padding: 1em;
    text-align: center;
}
main {
    padding: 1em;
}
.card {
    background: white;
    padding: 1em;
    margin-bottom: 1em;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}
footer {
    text-align: center;
    font-size: 0.9em;
    color: #666;
    padding: 1em;
}