There is a cosmetic issue in the representation of the horizontal menu (hornav) between different browser engines. In the horizontal menu a down arrow (j51-inline-icon) indicates the existence of a submenu under a menu item. That down arrow is displayed to the right of the main menu item in Mozilla Firebox, but is displayed below the main menu item in Chromium-based browsers like Chrome, Edge, and Vivaldi (s. attachments)
If it is possible to make that appear identical in all browsers, I would prefer the Firefox version, because the main menu items stay on one (invisible) line.
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Regards
Rolf