In the theme’s style.css file, around line 153 is this:
/* Secondary wrappers */
#nav-wrapper {
background-color:#78a5b6;
border-radius:60px 60px 0 0;
-webkit-border-radius: 60px 60px 0px 0px;
height:37px;
text-align:center;
font:normal 14px open_sans, Arial, sans-serif;
font-size: 0.875rem;
color:#fff;
position:relative;
z-index:1000;
}
You can override this if you are using a child theme or jetpack’s Edit CSS feature by changing the font line. Right now the font is open_sans, then if that isn’t available, it loads Arial, then sans-serif…etc. Always have a fallback font in case someone doesn’t have the ability to see the font you want, you can give a second choice.