body {
    background: #f0f2f5;
}
.register-box {
    max-width: 500px;
    margin: 60px auto;
    background: #fff;
    border-radius: 10px;
    padding: 30px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}
h2 {
    text-align: center;
    margin-bottom: 20px;
    color: #333;
}
.btn-primary {
    width: 100%;
}
.alert {
    text-align: center;
}