Yes, it is possible to include a fancy checkout page from the embedded/custom checkout section of Fondy while using the JavaScript API (IPSP library). You can achieve this by using Fondy's "Payment Page Designer". The Payment Page Designer allows you to customize the look and feel of your checkout page, and includes options such as custom colors, fonts, and logos. To use the Payment Page Designer, you'll need to create a payment button using the IPSP library. Once you have created a payment button, you can customize the checkout page by visiting the "Payment Page Designer" section in your Fondy dashboard. Here, you can make your desired changes and preview the result in real-time. Once you are satisfied with the design, you can save and publish your changes. To use the customized checkout page in your JavaScript code, you simply need to replace the default checkout URL with the URL of your customized checkout page. This URL can be found in the "Payment Page Designer" section of your Fondy dashboard.