Make the color change on hover of links in header

You can use CSS in a child theme or a CSS plugin (like Jetpack) to do this. I recommend using Firebug for CSS work–makes it much easier.

You’ll look in style.css for the .main-navigation section — this styles the navigation menu and links. Check for the :hover state (it may be li:hover a), and change the color property to whatever hex value you want to use.