Why doesn't :hover work to effect on other objects?

I'm new in html and css. In fact it's my first site i build in my learning. I've go a quesion. Why doesn't :hover effect work on the class i pointed it to?

I'd be really thankful for every help. But please explain, don't only tell me "how to".

I'm trying to get the search_type selector getting visible only after hoovering the "search" button

Thx in advance.

https:// codepen.io/_Hiderr/pen/bGGavQX