Color changes

Hello

I’m sorry to have to ask this here but I haven’t been able to find what I need elsewhere.
I am using a managed WordPress host (1&1). I really have no knowledge of web design and I’m learning as I go.

I’m using the MK Lite theme (although I have another issue with using the paid version, but will post in another area). I want to change the side menu bar background color as well as the hover over menu options color. In the Lite version I can get the text itself to change color when you hover but this is not what I want. I want the whole box the link is inside of to change color. (It is blue in the MK theme).

I’ve found a few lines of CSS that apparently is supposed to do it, but they are either incorrect or I am not using them correctly.

Thanks in advance.