Buttons in Dash App: highlight button that was last clicked

Hi, I have multiple groups of buttons and I want to highlight in each group the button with the highest timestamp. With group I just mean buttons within one single html parent element.
I am using dashR.

htmlDiv(className = "element_buttons", children = list(
        htmlButton('1', className = "buttons", id='one', n_clicks_timestamp=0),
        htmlButton('2', className = "buttons", id='two', n_clicks_timestamp=1),
        htmlButton('3', className = "buttons", id='three', n_clicks_timestamp=0)

In this case button ‘2’ should have a different background color.

Thank you very much :slight_smile:

I am looking for a solution in CSS or JS (or whatever).

Based on what I read regarding another topic, I found a way to do that with a callback. But I have so many buttons that would be very inefficient.

It seems to me this is a simple problem that many people should have encountered.

I would be very grateful if somebody shares their solution.