Fix mobile version of the main menu

[use-tusk[bot]]

Fixes #76

This PR addresses issues with the mobile version of the main menu. The main changes include:

• Improved visibility and accessibility of the sidebar toggle button on mobile devices.
• Enhanced the layout and structure of the sidebar for a better mobile experience.
• Made submenu toggle buttons more touch-friendly.
• Adjusted JavaScript functions to handle mobile and desktop transitions more effectively.
• Added functionality to close the sidebar when clicking outside of it on mobile devices.

These adjustments enhance the mobile responsiveness and usability of the sidebar menu while maintaining its desktop functionality.

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