Z-index not working for logos

I’m trying to make the logos on my website hover over the vertical line. I’ve set the z-index accordingly already, but it still doesn’t work:

Screen Recording 2023-12-12 at 3.23.08 PM

Anyone know what the issue is? Thanks so much!

Here is my site Read-Only: LINK
(how to share your site Read-Only link)

The z-index on the logo3_component element is set to Auto. If you set it to 4 it should render above the line which has a z-index of 3.