How to add class only on one page?

Question

css

There is a menu in which the first item is always underlined, since the active class has been added. How can I make it so that this class is only added on one page. Is there any solution through js?
https://codepen.io/vladimir2021794/pen/wvJxdbO

Answer 1

https://codepen.io/invfrontend/pen/ExWpXZv as an option.
This option will need to be upgraded if you want to highlight links depending on the page where you are at the moment. For a single specific link, this option is also suitable.