Bootstrap page menu links - text size

Is it possible to change the text size of the page menu links in a bootstrap (that appear above or below the banner)? One of our teachers would like the menu link text appear larger to match the 18pt text they have used throughout the site content. I couldn't see a property to change it, could it be achieved by a script?
Thanks.

You could add the styles optional property and add some css to target those links. This seems to do it:
#topnav li {
font-size: 18pt;
}

Many thanks, Fay - that works a treat!