Continuous slider with ligthbox: captions for thumbnails?

Hi,
Again Great plugin!
Questions:
1. How can I get a white background with css?
2 and the close icon and next and previous arrows far outside the enlarged images lik in the wp-featherligt plugin.
see for and example:

https://www.fromzero.nl

Thanks in advance

https://www.ads-software.com/plugins/continuous-image-carousel-with-lightbox/