NAVIGATION DROP DOWN BAR ON MOBILE SITE IS VERY LARGE

when my site is used on mobile display - the navigation dropdown is so large and scale off the mobile page. I wondered if there is a CSS code for this. Please can somebody help :)

@ccammidget no one can help without site url

thanks for your reply.its: www.fentonfilm.com

@ccammidge Add to Home > Design > Custom CSS

@media screen and (max-width:768px) {
a.nav-item-page {
   font-size: 16px;
}
}

thanks very much, problem is it has made the secondary navigation smaller but not the main navigation. It also still does not fit on page.Thank you

@ccammidge try this

@media screen and (max-width:768px) {
nav.mobile-primary-nav-links {
   font-size: 16px;
}
a.nav-item-page {
    font-size: 16px;
}
}

@media only screen and (max-width: 768px)
{
.mobile-primary-nav-links {
   font-size: 25px;
   letter-spacing: 0em;
   line-height: 2em;
}

.mobile-secondary-nav-links {
   font-size: 25px;
   letter-spacing: 0em;
   line-height: 1.9em;
}}