Flex is not working for responsive nav links

I have a nav bar with a div called “Nav Links”. It’s set to flex horizontal by default on desktop so that the menu links are horizontal.

When I resize to tablet and below, the menu is hidden, and I’d like it to be flex vertical so that the menu links are vertical. But changing the flex options does absolutely nothing. This “Nav Links” div seems to work differently than every other div on my site and I don’t know why.

Here is my site Read-Only: https://preview.webflow.com/preview/strong-by-bodyweight?utm_medium=preview_link&utm_source=designer&utm_content=strong-by-bodyweight&preview=89de4acb9bf0ecbf63a1a8838b76e0c4&workflow=preview