Input field unclickable (only on firefox)

Hello, there. I don't know when this started, but a few days ago, by chance, I accessed my site using firefox and noticed that the search input didn't work.

I thought, maybe, the text color was white (as the background), but you actually can't click the search field at all.

This happens only with Firefox.

Chrome, Safari and even Edge works fine.

Link on private information below.