I wanted to have a border-bottom instead of a background color for the highlighted menu item, to integrate the UI design choose by my client.
I see on the navigation component that we can style the color background or text.
I wanted to customize the button but couldn't find a selector or property indicating that the button is active
Tanks you @ZeroCodez this solution is interesting, but if i use a custom CSS it will potentially been overwritten by a new version of Retool.
I will take this solution as a last resort.