Store Page: Only have Products Display in Sub-Categories

Hi! Couple of queries relating to a store setup for an art gallery.

1. The store's collection includes the category 'Artists' and then subcategories for each artist (image attached). Is there a way to not have all of the products display when the top category 'Artists' is selected - just a blank page displaying until you click into a subcategory?

2. In mobile view, I'd like to create some space below the category (and sub-category) scroll bar as it appears right on top of the products at present. See attached image.

URL: https://red-ruby-y9nn.squarespace.com/
Pass: artwork

Thanks in advance for any help, much appreciated!

#1. You mean

this page: https://red-ruby-y9nn.squarespace.com/art/artists >> Show a blank page, no products on right?

#2. Add a space here?

Hello @tuanphan

So sorry, I must have missed your reply! 
Thank you for getting back to me on this - much appreciated.

Yes - as per your message above - that's right.
1. Looking to achieve a blank page on the head artists category.
2. Add a space below the category scroll bar on mobile. 

+ Sorry, I now have one more query relating to the scroll bar...
3. We have now published the site, and the scroll bar does not immediately appear, only when you hover on the category section, so it is not obvious that you can scroll. Is it possible to have the scroll bar appear on page load?

Thanks so much in advance for your help here.
Rebecca