Add rectangle to WebToolbarButton item?

Is it possible to add a rectangle to WebtoolbarButton item with PushButton style via JS and/or CSS?
Just want to make webtoolbar button items look like a ‘real-button’ with rectangle.

There is an example in bootstrap documentation for navbar component, but have no clue how to implement this in xojo.


<nav class="navbar navbar-light bg-light">
  <form class="container-fluid justify-content-start">
    <button class="btn btn-outline-success me-2" type="button">Main button</button>
    <button class="btn btn-sm btn-outline-secondary" type="button">Smaller button</button>