* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Arial', sans-serif;
    background-color: #f7f7f7;
    color: #333;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
}

h1 {
    text-align: center;
    font-size: 2rem;
    margin-bottom: 20px;
    color: #333;
}

form {
    background-color: #fff;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    width: 100%;
    max-width: 500px;
}

label {
    display: block;
    font-weight: bold;
    margin-bottom: 8px;
    color: #555;
}

select, input[type="number"], button {
    width: 100%;
    padding: 12px;
    margin-bottom: 20px;
    border-radius: 6px;
    border: 1px solid #ccc;
    font-size: 1rem;
}

select:focus, input[type="number"]:focus, button:focus {
    outline: none;
    border-color: #4CAF50;
}

button {
    background-color: #4CAF50;
    color: white;
    cursor: pointer;
    font-size: 1.1rem;
    transition: background-color 0.3s ease;
}

button:hover {
    background-color: #45a049;
}

input[type="number"] {
    width: 100%;
    padding: 12px;
    font-size: 1rem;
    border-radius: 6px;
    border: 1px solid #ccc;
    margin-bottom: 20px;
    box-sizing: border-box;
}

.payment-methods {
    display: block;
    margin-top: 20px;
}

.payment-method {
    background-color: #f1f1f1;
    padding: 15px;
    border-radius: 8px;
    text-align: center;
    width: 100%;
    cursor: pointer;
    transition: background-color 0.3s ease;
    margin-bottom: 15px;
}

.payment-method:hover {
    background-color: #ddd;
}

.payment-method img {
    max-width: 50px;
    max-height: 50px;
}

.payment-method p {
    font-size: 0.9rem;
    margin-top: 8px;
    color: #333;
}

.payment-method.selected {
    border: 2px solid #4CAF50;
}

#submit-btn {
    margin-top: 20px;
}

.error-message {
    color: red;
    font-size: 0.9rem;
    text-align: center;
    margin-top: 10px;
}

@media (max-width: 768px) {
    form {
        padding: 20px;
    }

    .payment-methods {
        grid-template-columns: 1fr 1fr;
    }

    input[type="number"], select, button {
        font-size: 0.9rem;
        padding: 10px;
    }
}