Dear @dmncn
It's a bit of a trick with just z-indexing alone. The whole system works on z-index:
Cover: z-index 1 (must be the lowest to slide underneath content)
Content: z-index 2 (must be higher to not be hidden by cover)
Site-title: z-index 3 (must remain above content).
So i think however you assign new z-indexing to the above three elements it wont work for example:
Cover: z-index 1 (must be the lowest to slide underneath content)
Content: z-index 2 (must be higher to not be hidden by cover)
Site-title: z-index 0 (must remain behind cover == but now hidden by content).
To use z-indexing for the site-title to be hidden then shown, the Cover must be higher than the image, but then it's also higher than the content and will not slide behind and therefore not be a cover.
I think to solve this problem you need some javascript or jquery that "at a certain scroll position the site-titles z-index changes from 0 to 3"
Best
Richard