Replace `border` to `outline` in `<NavItem>` to prevent jumping

[ai]

Right now, when I click in <NavItem> (package‘s tabs like Files, Versions) elements in navigation bar jumps by 1 px. The same behavior by moving :focus there by pressing Tab.

Here is an example from @sitnik/nanoid.

Grabacion.de.pantalla.desde.2025-02-22.20-53-25.mp4

It happens because on :focus we are adding border (which change element size). To avoid this problem it is recommended to use outline or box-shadow.

I suggest use outline for :focus style.

I also suggest use :focus-visible instead of :focus. This style will be added not on every click by only if user use keyboard navigation. It is also a good practice.

Sorry, I can’t send PR since I do not work with Tailwind CSS