.success-box {
    max-width: 600px;
    margin: 5rem auto;
    background: #fff;
    padding: 2.5rem;
    border-radius: 1rem;
    box-shadow: 0 0 20px rgba(0,0,0,0.1);
}
.icon-success {
    font-size: 4rem;
    color: #28a745;
}