Ays Pro Quiz Maker Start Button Color

Hello there!

I have tried many ways to change the color of the “Start” button at the bottom of the style section. I would like to know what is the code that I must enter in CSS to be able to change the color of the button and the text inside the button, everything else like pading, size etc is perfect but the color is missing, now I have a white color in the button and not match my page. If it is possible I will like the Black Button with White Text. Thank you very much in advance.

This is the code from the inpect page on Google:

<input type=”button” class=”ays_next start_button action-button” value=”Start” data-enable-leave-page=”false”>

The page I need help with: [log in to see the link]