the bar is separated completely from the buttons.

Absolute positioning and some transitions

you dont need to absolutely position anything.

Mind sharing a code pen of what you mean?

of how flex works? or how client side calculated js works? or what?
you just get the ref of the button on click, and modify left margin and the max width based on pixel difference of the clicked vs the current location. when you set transition all on the css it will handle the rest

Of how the flex part works

tailwind has some pretty clear docs on it. id personally use grid + flex to ensure equally spaced buttons, putting a min px-2 around the inner text span so the longest text doesnt look choked

Yeah, that's just how I've done it in the past. Def can use refs/flex

You can use Tailwind CSS Peer

https://x.com/surjithctly/status/1612831829987590144?s=20

You just taught me about something I had no idea existed...this is really cool

Does this just create a pill or how can we style it to become an underline? I looked at your play link but didn’t see any customization options

didn’t you see the code? try on desktop