You need to edit the stylesheet (style.css) on the theme editor.
Back up the file just in case you screw up!
Then look for the places where it says hover:
If you’re not familiar with editing css files, you need a little bit of trial and error until you find the exact hover color you want to change.
Oh, and you need to know the color code. There must be easier ways to do that, but I’m stupid, so I go to front page, write something on the color I want, and check the code on the source code.
