CSS image not showing

https://www.stimadesigns.com/Elysian/

I am using CSS that I’ve never used before. If you look at my homepage, below my menu, I have a section that fades from white to transparent. In the white collection my logo is supposed to appear, but for some reason, it is underneath. You can see it peeking out a little bit. I tried changing the z index but that didn’t work. I’m sure I did something wrong with the CSS because this is the first time using the :before.