body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f5f5f5;
    color: #333;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100vh;
}

header {
    width: 100%;
    text-align: center;
    margin-bottom: 20px;
    background-color: #333;
    padding: 10px 0;
}

.logo {
    width: 120px;
}

.container {
    background: white;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    text-align: center;
    width: 90%;
    max-width: 400px;
}

h1 {
    color: #555;
}

.checkout-button {
    background-color: #007BFF;
    color: white;
    border: none;
    padding: 10px 20px;
    font-size: 16px;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.checkout-button:hover {
    background-color: #0056b3;
}

@media (max-width: 600px) {
    .container {
        padding: 15px;
        font-size: 14px;
    }
    .checkout-button {
        width: 100%;
        font-size: 18px;
    }
}