Nav-button

I successfully added a donate nav button to a website last night but when I just did the same thing to another site, it didn't work, here's what I did:

I added "nav-botton" to the menu item css classes
.
This is all that's in my additional css:
@media (max-width: 768px) {
.mobile-header-navigation .site-logo.mobile-header-logo img {
height: 108px;
}
.menu-toggle, .main-navigation .mobile-bar-items a {
line-height: 108px;
}
}
@media (max-width: 768px) {
.navigation-branding img, .site-logo.mobile-header-logo {
height: 108px;
}
}

@media (min-width:769px) {
.main-navigation .main-nav ul li.nav-button a {
background-color: #ffffff;
border: 2px solid #000000;
color: #000000;
line-height: 35px;
}
}