full width picture over a page doesn’t work

Hello everyone,
unfortunately I have another problem. I found a great gallery on another website. I also tried to recreate them on my website. Unfortunately, this did not work. The address of the page from which I would like to copy it is http // www fotissima de/portfolio-items/pilze/ (you have to add points at the spaces, to use the link). If I enter this code:

<div class="item" style="background-image:url(https://philippfalkenhagen.de/wp-content/uploads/2019/07/Reh-im-Mohnfeld.jpg); width: 100%; height: 90vh; background-position: center center; background-size: cover; z-index: 0;">
					<div class="container">
					<div class="format-standard">
												
					</div>	
				</div>	
			</div>

It works about, but only on the start page, which helps me a little. Although the picture does not cover the entire page. Can someone help me?

Kind regards

The page I need help with: [log in to see the link]