How to make a menu for a site similar to wildberries?

Question

css

There is a site (local) that needs to be done so that when you hover over a menu item, it becomes active and remains active when the list of subcategories is displayed. To make it clearer, you need the same menu operation as on https://www.wildberries.ru/ I understand that this is js and the mouseover and mouseout properties, but I don’t know how to do it. Tell me please.

Answer 1

I'm not making a discovery when I say this is done without JS, in pure CSS using :hover. More or less like this:

<span class="menu-item">
  О компании
  <div class="submenu">
    Основана вчера, продаём телефоны, звоните...
  </div>
</span>
<style>
  .menu-item > .submenu { display: none; }
  .menu-item:hover > .submenu { display: block; }
</style>

Answer 2

https://jsfiddle.net/QW01_01/q0yt211p/9/