Im trying to create my own booking widget integrated with little hotelier

Im trying to create my own booking bar for this hotel Im working with. They are subscribed to Little Hotelier and they want to keep using the platform for their booking system.

The thing is, their widget is a bit old looking and i can´t style it directly in webflow. So i guess my only option is to create my own. The thing is Im not an expert developer.

Any guidance?

Below you can see the website, the box below is their original widget and the one above is the goal.

Here is my site Read-Only: Webflow - Hotel Real de Minas