[FEAT] Dynamic Underline Effect for Navbar Items on Hover

[bro-maanii]

I propose adding a dynamic underline effect to the navbar items to enhance the user experience. When a user hovers over a navbar item (such as "About," "Project," or "Contact"), a subtle underline should appear below the item. Additionally, when the user navigates to a specific page (e.g., the About page or Project page), the underline should persist below the corresponding navbar item to provide visual feedback and improve navigation clarity. This dynamic underline effect will contribute to a more engaging and user-friendly interface.