creating a menu in CSS

Is your site with this menu up somewhere live currently? That could help guide you a bit more specifically.

This would be a great resource to apply to your own code: http://www.w3schools.com/css/css_navbar.asp

I can definitely try! Something to keep in mind is that WordPress applies additional classes, etc. to it’s menu + items so the selectors you would be using for your code example currently would most likely shift once you “transfer” your menu items into the WordPress dashboard.

#nav li {
  display: inline-block;
  padding: 10px 20px;
  background-color: pink;
}

#nav li a {
  text-decoration:none;
  color: purple;
}

This would be a starting point. Are there specific question I can assist with?

#nav {
   border-top: 2px solid black;
   border-bottom: 2px solid black;
}

Would add the lines on the top/bottom.