Integration with Wishlist Member (custom CSS to add?)

I am currently using WishList Member (v2.80) to manage members for my site.

I would like to use Humancaptcha to accommodate the vision-impaired.

I have set Humancaptcha to “yes” for registration page, but perhaps because I am using another plugin’s registration page, Humancaptcha is not appearing.

Here is our registration page:
https://sacredstory.net/index.php?/register/SSI-2012/

Is there any way I can use a shortcode or custom CSS to implement the Humancaptcha on the WishlistMember registration page?

Thanks!

https://www.ads-software.com/plugins/humancaptcha/