Strange error has occurred on drop down menu

Site URL: https://bumblebee-pelican-d4t5.squarespace.com/log/2019/3/11/monmouth-glacier-ak-e7j2m-h65wz

An issue has occurred, seemingly out of nowhere, where the text on the drop down menu now becomes blocked out. The code is set to transparent, which was working fine til now. Any ideas how to correct this?

I'll attach an image so it's clear.

Thanks!

Hi. Your site is private. Can you setup password & share url again? We can check easier