I’m having trouble finding how to do this or even the proper terminology. I want a new page to open when a visitor clicks on a link, but the page to open and load in the forefront without leaving the main page. Producthunt.com is a good example of this feature. Once you click on the product, it opens up the description page, but you can click outside of the box to go back to the main page. Reddit also had this feature for a while.
for a fluid and smooth transitions between your website’s pages, you could try implement something like barba.js. Did you have a look at it yet?
There is a cloneable project on the webflow showcase using it:
Hope this helps!