Andrew Nevins
(@anevins)
WCLDN 2018 Contributor | Volunteer support
Add:
.primary-navigation {
margin: 0;
float: none;
}
.primary-navigation .nav-menu {
display: table;
margin: 0 auto;
}
.primary-navigation a {
margin: 0 20px;
}
You probably want to apply that in a media query just for desktops too.
By the way if you’re customising the Twenty Fourteen theme without creating a Child Theme then you lessen the chances of us being able to help you, because it turns into a custom theme.