Unnecessary space in widget

I successfully installed the plugin and it works well. There is a small design problem, which I could not yet overcome:

In the widget, there is a large space between the widget title and the input box. How do I decrease this space? Is that a question of CSS?

Here is how it looks: https://ledapathfinders.org/

Regards and thanks

https://www.ads-software.com/plugins/wysija-newsletters/