Hey Patrick,
In that case, please add this code to the Navigation Inline > Element CSS.
$el a:hover .x-anchor-text-primary {
font-weight:bold !important;
}
For global implementation, you can also try updating your previous code to this:
a:hover .x-anchor-text-primary {
font-weight:bold !important;
}
Just note that I was able to provide a custom code because this only requires a few lines of code or is simple. We could not always do this moreover that this is outside the scope of our support. This only serves as a guide.
Hope that helps.