If the files you're trying to link come with your application, and you're using .ep, use the taghelpers
https://metacpan.org/pod/Mojolicious::Plugin::TagHelpers#stylesheet
https://metacpan.org/pod/Mojolicious::Plugin::TagHelpers#javascript

They all make use of https://metacpan.org/pod/Mojolicious::Controller#url_for to resolve your paths, to always make correct urls even if your apps path changes

I make use of javascript and url_for in Mojolicious::Lite +and jQuery +AJAX + Mojo::Template and *cough* Re: calling menu bar creating code from another cgi/pl code (mojo)