body {
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

.card {
    background: white;
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.2);
    text-align: center;
    max-width: 400px;
}

h1 {
    color: #333;
}

button {
    background-color: #764ba2;
    color: white;
    border: none;
    padding: 10px 20px;
    font-size: 16px;
    border-radius: 5px;
    cursor: pointer;
    transition: background 0.3s;
}

button:hover {
    background-color: #5a3682;
}

#message {
    margin-top: 15px;
    color: #28a745;
    font-weight: bold;
}

.hidden {
    display: none;
}