Menu style

Hi everyone, I’d like a hand on a project I’m working on. First of all I’m a new WordPress user and I really appreciate any help given by any of you.

What I need is simply change the style of my menu on top of my web page. I already changed the background but there’s still lots to do, such as change font color and size, and get rid of those separations bars between the cells.

So all I need is to change font size, color and get rid of the separation bars between cells on the menu.

Can anyone help me?

the link is http://www.acsconsultoria.com.br/wp
The content is in Portuguese, sorry for that 🙁