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

header {
    padding: 50px 20px;
    background: linear-gradient(135deg, #4f46e5, #06b6d4);
}

h1 {
    margin: 0;
    font-size: 2.5rem;
}

main {
    padding: 40px 20px;
}

.card {
    background: #1e293b;
    margin: 20px auto;
    padding: 20px;
    border-radius: 12px;
    max-width: 400px;
    box-shadow: 0 10px 20px rgba(0,0,0,0.3);
}

button {
    margin-top: 20px;
    padding: 10px 20px;
    border: none;
    background: #22c55e;
    color: white;
    font-size: 16px;
    border-radius: 8px;
    cursor: pointer;
}

button:hover {
    background: #16a34a;
}

footer {
    margin-top: 40px;
    padding: 20px;
    font-size: 12px;
    opacity: 0.7;
}