body {
    margin: 0;
    font-family: Arial, sans-serif;
    background: #0f172a;
    color: white;
}

header {
    padding: 20px;
    text-align: center;
    background: #1e293b;
}

main {
    padding: 15px;
}

.card {
    background: #1e293b;
    padding: 15px;
    margin-bottom: 15px;
    border-radius: 10px;
}

button {
    padding: 10px;
    border: none;
    border-radius: 8px;
    background: #22c55e;
    color: white;
    font-weight: bold;
}