Conditinal display of navigation links

Hi,
I would like to display the navigation links below the single post (previous, next) only for my custom post type “book”. For pages and posts, I would like to hide the navigation links.

I managed to hide the navigation links for all types with the following additional CSS instruction:
`.nv-post-navigation{display: none;}

But how can I make this only effective for posts and pages?
All hints will be much appreciated!

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