body {
    background: linear-gradient(135deg, #0f2027, #203a43, #2c5364);
    font-family: Arial, sans-serif;
    height: 100vh;
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    color: white;
}
.card {
    background: rgba(0,0,0,0.4);
    padding: 40px;
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 10px 30px rgba(0,0,0,0.5);
    max-width: 400px;
}
.btn {
    display: inline-block;
    margin-top: 20px;
    padding: 15px 25px;
    background: #00c6ff;
    color: black;
    font-weight: bold;
    text-decoration: none;
    border-radius: 8px;
}