This will require a developer on your end to implement. We cannot assist you.
If you want full control over the look of your Impact Calculator, you may want to build your own.
The data that powers the Impact Calculator can be retrieved via API. This will allow you to fetch the most recent donation totals so that you can create your own calculator.
You can fetch the data via JSON with the following URL:
Replace "<your-widget-id>" with the widget ID provided in your embed code. See screenshot for an example: