body { background-color: #ece5dd; font-family: sans-serif; display: flex; justify-content: center; padding: 20px; }
#chat-container { width: 100%; max-width: 400px; background: white; padding: 20px; border-radius: 10px; }
.btn { display: block; background: #25d366; color: white; padding: 15px; text-align: center; text-decoration: none; border-radius: 5px; margin-top: 10px; }
#checkout-button { transition: opacity 0.5s; }