Custom Navigation Size/Color CSS on Landing Page?

So I'm hoping this isn't a well trod/previously well explained issue, but I'm hitting a block trying to format the navigation on a landing page - the nav settings within the page customizer don't seem to change what I'm seeing displayed/at most have changed the size of the navigation font *within* the site, but not on this page.

What I'd really like is to have the nav links display larger (the 'branding' text here/my name says it's displaying at 200px but now I wonder if I can trust that...) and *if possible* I'd really like to set their 'hover' color to match the bright yellow of the branding text (hsl(58, 100%, 55%))

Maybe complicating factor but I have a small bit of custom CSS already on my site (eliminating underlines for nav links) - I don't think it's what's giving me this current issue tho...

Thanks everyone and hoping this is in someway useful to the community/scaleable! 

Can you share site url?

@tuanphan Apologies! for some reason I thought it was in there... https://www.sambooker.com/

You can add this code to Cover Page Header Code Injection

<style>
  li a:hover {
    color: hsl(58, 100%, 55%) !important;
}
</style>