Edit color border and font of Elgg Menu Nav

Hi to all! 

I would like to change the font and the color of Elgg menu, simply I would to do it with background white (like body) and change button color and border.

I attach an image for explain better what I would like. https://postimg.cc/image/l0lugewp7/

Anyone can tell me what css code I have to write (I am using GalliCSS plugin to modify), i have modified the Elgg Button with this code:

p, body {
    font-family: "Segoe UI",Tahoma,Calibri,Trebuchet MS,sans-serif;
    font-size: 14px;
.elgg-button {

font-size: 16px;
font-family: "Calibri",Tahoma,Calibri,Trebuchet MS,sans-serif;
font-weight: bold;

-webkit-border-radius: 5px;

-moz-border-radius: 5px;

border-radius: 5px;

width: auto;

padding: 2px 4px;

cursor: pointer;

outline: none;

-webkit-box-shadow: 0px 1px 0px rgba(0, 0, 0, 0.40);

-moz-box-shadow: 0px 1px 0px rgba(0, 0, 0, 0.40);

box-shadow: 0px 1px 0px rgba(0, 0, 0, 0.40);




I am not an expert, so I don't know what code need to have what I would.

Thank you all!