Arrows in Product Page Carousel View almost invisible

Site URL: https://iris-owl-rwdf.squarespace.com/config/

Hi, i have just noticed that the arrows on my listed products are almost invisible. I have tried a dozen different CSS codes on here to try to fix, but  nothing works. 

My question is this:

- can the arrows be made larger, thicker and instead of looking like this "<>" more like this ←→

- i'd also like to change the background colour of the arrow to make it stand out more. Feedback from consumer research is indicating that both on tablets and mobiles the current arrows are impossible to see.

https://iris-owl-rwdf.squarespace.com/config/

pw: view

The site is live so maybe the pw is no longer needed?

Many thanks,

Kathy

Hi,

Can you share link to exact page? We can check easier