Fullscreen scrolling issue

I’m creating this theme for wordpress https://enovastudio.org/wordpress-demo/photographer/category/blog/ , the background is a fullscreen image that get’s expanded automatically, basically i’m using the css from this plugin https://nanotux.com/blog/fullscreen/ but without the javascript (with css i’m expanding the image at 100% height and width with hidden overflow)

Now if you take a look at the blog category here https://enovastudio.org/wordpress-demo/photographer/category/blog/ , when there is to much content on the page, the scroll appears (as it should) , but it doesn’t work as it should, a part of the content stay hidden and i can’t scoll.

Any advice ?

Thanks…