Change hover link colour

Hi,
I’m having difficulty to change the colour of my links in my theme (North).
The main menu in my header turns white when hovered over it. This should stay like this, however I want the sub menu’s to change to red when hovered over it.

Also in my footer and blog post title. This is currently invisible. It’s frustrating as I’ve tried everything, and the theme support is not helpful.
Hope you can help a desperate newbie.

My theme has a section where I can post customised css code. Thanks!