A11y | Main navigation (Part 2)

[zoglo]

Followup of #53

Description

• Improve the accessibility-navigation JavaScript 832b2f3

  • close on lost focus (either new focus via hover / active element on focus-tab)
  • handle the aria states for each item and close them accordingly
  • handle the proper events
  • Remove the previously added aria-role: none from list elements
  • main navigation | accessibility Improvements  #58 - Sub-navigation should close on ESC or when leaving the sub-navigation -> Close and handle all previously open dropdowns when pressing ESC

• Handle infinite navigation levels within the main-navigation ddfc2c2

  • This one adds the same handling for navigations past level_2 in case people would activate them. This has been added to properly implement the accessibility-navigation JavaScript due to the need of handling multiple levels.

• Implements high contrast mode for the navigation

  • main navigation | accessibility Improvements  #58 - Fix icons in high-contrast mode -> The expand icons + main toggle were reworked in 55a5a77 and 832b2f3
    

• Consider focus for all buttons on MacOS 011f21c

  • This one actually does not make sense if we want to be accessible since it's a pure design normalizer that would just remove it completely...

Context

Please mind that using :hover for any navigation dropdown that can not be closed by a mechanism is not accessible based on:
https://www.w3.org/WAI/WCAG21/Understanding/content-on-hover-or-focus

Dismissible
A mechanism is available to dismiss the additional content without moving pointer hover or keyboard focus, unless the additional content communicates an input error or does not obscure or replace other content;

Aka - Dismissable via ESC https://bitvtest.de/pruefschritt/bitv-20-web/bitv-20-web-9-1-4-13-eingeblendete-inhalte-bedienbar

[zoglo]

I'd rather add the focus trap on mobile in this PR than the next :)

[sascha-mueller]

Many thanks for your efforts and all the work you have put into it. It looks good